zio deadlock #496
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It looks like you've found a deadlock which must be more likely to occur with your particular workload. From that stacks you posted it looks like the following has occurred.
The full list of stacks can be found here in the mailing list archive. |
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Thanks Brian. In case that's of any help, here's the Blocked State ouput from another occurrence (this time with the only thing happening being nbd-server writing to the zvol (from a strace, in 31 * 4kB write(2)s). As I said on the ML, if I limit the rate at which the data is being transferred and written to the zvol, it doesn't occur. Otherwise, it does occur quite consistently after a few GB of data transferred. |
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If you can reliably reproduce this issue it would be interesting to see the output of "zpool events -v" once that deadlock has happened. |
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2011-12-17 04:29:51 -0800, Gunnar Beutner:
The thing is that I can't run anything when that happens and Stephane |
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If you set the |
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Thanks. I just did that. New occurrence, no event. I did get the "statechange" events upon mounting the FS, nothing after that. Transfered some data maxing out the 1Gb/s. It hung after about 90GB were transfered. |
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I had a similar issue after updating the kernel to 3.0.0-14-server. Downgrading to 3.0.0-13-server solved this for me. |
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I think I am experiencing this issue consistently on heavy I/O on my storage server. I am using Ubuntu Server (Oneiric) and the issue occurred initially while using kernel 3.0.0-13. I upgraded my kernel version and zfs to the latest version hoping for a fix, but it happened again under a similar load. So unlike user "tisoft" above me I experience this issue both with 3.0.0-13 and 3.0.0-15. In my case the deadlock occurred while running the All of the following data was acquired in a single session following a deadlock that I caught before the whole system crapped its pants. Output of uname -a: Output of dpkg -l | egrep 'zfs|spl': Here is the output of zpool status on the affected filesystem: Here is the trace from the syslog: Output of zpool events -v following deadlock: Hopefully relevant output of ps following deadlock: |
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I was able to reproduce this issue running a test case which simply creates a large number of files in the filesystem. After running for 10 hours and creating 224 million files the system deadlocked. The root cause appears to be that the z_null_iss thread got stuck on the mutex's wait_lock when attempting to drop a zio mutex. Unfortunately, despite significant investigation I was unable to determine what thread was holding the spin lock. Regardless, here's the detailed analysis. One of several threads creating files, it's block waiting for the txg to sync. PID: 5597 TASK: ffff88062ecb00c0 CPU: 7 COMMAND: "cm"
#0 [ffff8804fccb9a58] schedule at ffffffff814ee4a0
#1 [ffff8804fccb9b20] cv_wait_common at ffffffffa04d34ec [spl]
#2 [ffff8804fccb9ba0] __cv_wait at ffffffffa04d3623 [spl]
#3 [ffff8804fccb9bb0] txg_wait_open at ffffffffa061136b [zfs]
#4 [ffff8804fccb9c10] dmu_tx_wait at ffffffffa05d6c2d [zfs]
#5 [ffff8804fccb9c40] zfs_create at ffffffffa0644e9f [zfs]
#6 [ffff8804fccb9d20] zpl_create at ffffffffa0658817 [zfs]
#7 [ffff8804fccb9d90] vfs_create at ffffffff81184dd4
#8 [ffff8804fccb9dd0] do_filp_open at ffffffff811889df
#9 [ffff8804fccb9f20] do_sys_open at ffffffff81174b99
#10 [ffff8804fccb9f70] sys_open at ffffffff81174cb0
#11 [ffff8804fccb9f80] system_call_fastpath at ffffffff8100b0f2
RIP: 00002aaaaada5200 RSP: 00007fffffffd888 RFLAGS: 00010246
RAX: 0000000000000002 RBX: ffffffff8100b0f2 RCX: 0000000000000000
RDX: 00000000000001a4 RSI: 0000000000000042 RDI: 0000000000601e40
RBP: 00007fffffffe2b0 R8: 0000000000000000 R9: 0000000000000001
R10: 00000000fffffff0 R11: 0000000000000246 R12: ffffffff81174cb0
R13: ffff8804fccb9f78 R14: 0000000000000000 R15: 0000000000000000
ORIG_RAX: 0000000000000002 CS: 0033 SS: 002b
The txg_sync thread which is responsible for ensuring txg are synced in a reasonable time, it's blocked waiting on an outstanding write. PID: 5333 TASK: ffff88062f6db580 CPU: 7 COMMAND: "txg_sync" #0 [ffff880636a99850] schedule at ffffffff814ee4a0 #1 [ffff880636a99918] cv_wait_common at ffffffffa04d34ec [spl] #2 [ffff880636a99998] __cv_wait at ffffffffa04d3623 [spl] #3 [ffff880636a999a8] zio_wait at ffffffffa065480b [zfs] #4 [ffff880636a999d8] dbuf_read at ffffffffa05c3fa9 [zfs] #5 [ffff880636a99a98] dbuf_will_dirty at ffffffffa05c5cf6 [zfs] #6 [ffff880636a99ad8] dmu_write at ffffffffa05cc3b0 [zfs] #7 [ffff880636a99b58] space_map_sync at ffffffffa060fd2a [zfs] #8 [ffff880636a99c48] metaslab_sync at ffffffffa05fa93a [zfs] #9 [ffff880636a99cc8] vdev_sync at ffffffffa06141ff [zfs] #10 [ffff880636a99d18] spa_sync at ffffffffa06003eb [zfs] #11 [ffff880636a99de8] txg_sync_thread at ffffffffa0611c61 [zfs] #12 [ffff880636a99eb8] thread_generic_wrapper at ffffffffa04cb748 [spl] #13 [ffff880636a99ee8] kthread at ffffffff810906a6 #14 [ffff880636a99f48] kernel_thread at ffffffff8100c14a A child read zio which was issued as a consequence on the aforementioned requested write, it blocked on its parents zio mutex. PID: 5210 TASK: ffff8806358c3540 CPU: 7 COMMAND: "z_rd_iss/7" #0 [ffff88062f64fc30] schedule at ffffffff814ee4a0 #1 [ffff88062f64fcf8] __mutex_lock_slowpath at ffffffff814efb3e #2 [ffff88062f64fd68] mutex_lock at ffffffff814ef9db #3 [ffff88062f64fd88] zio_ready at ffffffffa0654d78 [zfs] #4 [ffff88062f64fde8] zio_execute at ffffffffa06546c9 [zfs] #5 [ffff88062f64fe18] taskq_thread at ffffffffa04cc6c2 [spl] #6 [ffff88062f64fee8] kthread at ffffffff810906a6 #7 [ffff88062f64ff48] kernel_thread at ffffffff8100c14a The z_nul_iss thread which is holding the parent zio mutex and blocking the child zio. It's attempting to drop the mutex but in the process it must take the mutex's wait_lock to safely wake all waiters. The spin lock however is contended and we spin on it consuming an entire cpu, this is easily visible in top. #6 [ffff880636b0fd50] _spin_lock at ffffffff814f0dce #7 [ffff880636b0fd58] __mutex_unlock_slowpath at ffffffff814ef735 #8 [ffff880636b0fd78] mutex_unlock at ffffffff814ef70b #9 [ffff880636b0fd88] zio_ready at ffffffffa0654cf0 [zfs] #10 [ffff880636b0fde8] zio_execute at ffffffffa06546c9 [zfs] #11 [ffff880636b0fe18] taskq_thread at ffffffffa04cc6c2 [spl] #12 [ffff880636b0fee8] kthread at ffffffff810906a6 #13 [ffff880636b0ff48] kernel_thread at ffffffff8100c14a ...unfortunately I couldn't determine what (if anything) is holding that spin lock. I dug up the exact memory location for the lock in memory and dumped its contents but everything looks sane. I even verified that the one task struct listed as a waiter on this list is the previous thread. Here's the lock in memory. crash> p *(struct mutex *)0xffff88017c00b678
$9 = {
count = {
counter = -1
},
wait_lock = {
raw_lock = {
slock = 131074
}
},
wait_list = {
next = 0xffff88062f64fd10,
prev = 0xffff88062f64fd10
},
owner = 0x0
}
So two possible explanation for this are:
The next step is going to have to be to reproduce this issue with CONFIG_DEBUG_SPINLOCK set. This will allow us to identify the task struct which owns the spin lock. I was unable to do this simply by looking at all the stack traces. |
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Brian, is it possible that a thread freed this lock, but the free wasn't done correctly? |
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In the above mutex, it shows |
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@prakash-surya That's to be expected since we're past the point in mutex_unlock() which clears the owner. |
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I ran |
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Thanks Prakash, I should also update this issue with our current thinking of how this bug must be happened... even if we can't reproduce it. The only scenario I can think of which entirely explains this issue is a use-after-free bug as follows.
This effectively results in the deadlock observed above although the race for this to occur is only a few instructions wide. However, we do have some evidence that this is exactly what happened if you look at the value of the ticket spinlock above it is set to 0x00020002 which indicates it was recently initialized. This value is far to low for anything but a new zio since it gets incremented every mutex_enter() or mutex_exit(). Unfortunately, I haven't been able to find the exact call path where this is happening and it's been difficult to reproduce. Incidentally, this issue could potentially go unobserved in other ports. The only reason this is causing a problem on Linux is because of the nitty gritty details of how an x86_64 spin lock is implemented. This could easily not cause an issue for an alternate mutex implementation. |
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The above patch isn't a fix, but it might help avoid the problem by moving the mutex_init call to an constructor for the slab which will be called far far far less frequently. If someone who is suffering from this issue could try and patch it would be helpful. Incidentally, you can tell if this is the issue your suffering from by checking to see if one of the z_* threads is consuming 100% of one cpu when it occurs. |
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I've been using ZFS with this patch for almost 3 days now, and so far so good. The systems in question were under a good amount of load (several large file copies to the zpool, multiple recv operations, etc) and nothing has failed yet. |
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@asnow0 Is it safe to assume you were hitting this deadlock regularly prior to this patch? |
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I had this deadlock regularly before this patch. The server is now running 4 days with the patch and I didn't get the deadlock. |
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@prakash-surya yes, I was seeing this issue pretty frequently before applying the patch. |
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Add a standard zio constructor and destructor. Normally, this is done to reduce to cost of allocating a new structure by reducing expensive operations such as memory allocations. However, in this case none of the operations moved out of zio_create() were really very expensive. This change was principly made as a debug patch (and workaround) for a zio_destroy() race. The is good evidence that zio_create() is reinitializing a mutex which is really still in use by another thread. This would completely explain the observed symptoms in the issue report. This patch doesn't fix the root cause of the race, but it should make it less likely by only initializing the mutex once in the constructor. Also, this particular flaw might have gone unnoticed in other zfs implementations due to the specific implementation details of Linux ticket spinlocks. Once the real root cause is determined and resolved this change can be safely reverted. Until then this should help workaround the issue. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #496
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I've merged this workaround in the master because we have good evidence that it does help avoid the issue. However, I'm going to leave this issue open until we resolve the real root cause at which point the workaround can be reverted. |
This was referenced Mar 12, 2012
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behlendorf
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Add a standard zio constructor and destructor. Normally, this is done to reduce to cost of allocating a new structure by reducing expensive operations such as memory allocations. However, in this case none of the operations moved out of zio_create() were really very expensive. This change was principly made as a debug patch (and workaround) for a zio_destroy() race. The is good evidence that zio_create() is reinitializing a mutex which is really still in use by another thread. This would completely explain the observed symptoms in the issue report. This patch doesn't fix the root cause of the race, but it should make it less likely by only initializing the mutex once in the constructor. Also, this particular flaw might have gone unnoticed in other zfs implementations due to the specific implementation details of Linux ticket spinlocks. Once the real root cause is determined and resolved this change can be safely reverted. Until then this should help workaround the issue. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue openzfs#496
ryao
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The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest. /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 The backtrace was an infinite loop of `vdev_queue_io_to_issue()` invoking `zio_execute()` until it overran the stack. vdev_queue_io_to_issue() will ony invoke `zio_execute()` on raidz vdevs when aggregation I/Os are generated to improve aggregation continuity. These I/Os do not trigger any writes. However, it appears that they can be generated in such a way that they recurse infinitely upon return to `vdev_queue_io_to_issue()`. As a consequence, we see the number of parents by 1 each time the recursion returns to `vdev_raidz_io_start()`. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
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Oct 9, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest. /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 The backtrace was an infinite loop of `vdev_queue_io_to_issue()` invoking `zio_execute()` until it overran the stack. vdev_queue_io_to_issue() will ony invoke `zio_execute()` on raidz vdevs when aggregation I/Os are generated to improve aggregation continuity. These I/Os do not trigger any writes. However, it appears that they can be generated in such a way that they recurse infinitely upon return to `vdev_queue_io_to_issue()`. As a consequence, we see the number of parents by 1 each time the recursion returns to `vdev_raidz_io_start()`. Signed-off-by: Richard Yao <richard.yao@clusterhq.com>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 9, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest. /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 The backtrace was an infinite loop of `vdev_queue_io_to_issue()` invoking `zio_execute()` until it overran the stack. vdev_queue_io_to_issue() will ony invoke `zio_execute()` on raidz vdevs when aggregation I/Os are generated to improve aggregation continuity. These I/Os do not trigger any writes. However, it appears that they can be generated in such a way that they recurse infinitely upon return to `vdev_queue_io_to_issue()`. Signed-off-by: Richard Yao <richard.yao@clusterhq.com>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 10, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 10, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 10, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 10, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 10, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 10, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 11, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
ryao
added a commit
to ryao/zfs
that referenced
this issue
Oct 11, 2014
The below excerpt of a backtrace is from a ztest failure when running ZoL's ztest: /openzfs#453 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#454 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350003de0) at ../../module/zfs/vdev_queue.c:747 /openzfs#455 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350003de0) at ../../module/zfs/zio.c:2659 /openzfs#456 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1399 /openzfs#457 zio_nowait (zio=0x7f0350003de0) at ../../module/zfs/zio.c:1456 /openzfs#458 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350003a10) at ../../module/zfs/vdev_mirror.c:374 /openzfs#459 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1399 /openzfs#460 zio_nowait (zio=0x7f0350003a10) at ../../module/zfs/zio.c:1456 /openzfs#461 0x00007f03c806464c in vdev_raidz_io_start (zio=0x7f0350003380) at ../../module/zfs/vdev_raidz.c:1607 /openzfs#462 0x00007f03c807f243 in __zio_execute (zio=0x7f0350003380) at ../../module/zfs/zio.c:1399 /openzfs#463 zio_nowait (zio=0x7f0350003380) at ../../module/zfs/zio.c:1456 /openzfs#464 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002fb0) at ../../module/zfs/vdev_mirror.c:374 /openzfs#465 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1399 /openzfs#466 zio_nowait (zio=0x7f0350002fb0) at ../../module/zfs/zio.c:1456 /openzfs#467 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033957ebf0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#468 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:2707 /openzfs#469 0x00007f03c808285b in __zio_execute (zio=0x7f033957ebf0) at ../../module/zfs/zio.c:1399 /openzfs#470 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f0390001330, pio=0x7f033957ebf0) at ../../module/zfs/zio.c:547 /openzfs#471 zio_done (zio=0x7f0390001330) at ../../module/zfs/zio.c:3278 /openzfs#472 0x00007f03c808285b in __zio_execute (zio=0x7f0390001330) at ../../module/zfs/zio.c:1399 /openzfs#473 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4013a00, pio=0x7f0390001330) at ../../module/zfs/zio.c:547 /openzfs#474 zio_done (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:3278 /openzfs#475 0x00007f03c808285b in __zio_execute (zio=0x7f03b4013a00) at ../../module/zfs/zio.c:1399 /openzfs#476 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014210, pio=0x7f03b4013a00) at ../../module/zfs/zio.c:547 /openzfs#477 zio_done (zio=0x7f03b4014210) at ../../module/zfs/zio.c:3278 /openzfs#478 0x00007f03c808285b in __zio_execute (zio=0x7f03b4014210) at ../../module/zfs/zio.c:1399 /openzfs#479 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03b4014620, pio=0x7f03b4014210) at ../../module/zfs/zio.c:547 /openzfs#480 zio_done (zio=0x7f03b4014620) at ../../module/zfs/zio.c:3278 /openzfs#481 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03b4014620) at ../../module/zfs/zio.c:1399 /openzfs#482 zio_execute (zio=zio@entry=0x7f03b4014620) at ../../module/zfs/zio.c:1337 /openzfs#483 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#484 0x00007f03c806106e in vdev_queue_io (zio=zio@entry=0x7f0350002be0) at ../../module/zfs/vdev_queue.c:747 /openzfs#485 0x00007f03c80818c1 in zio_vdev_io_start (zio=0x7f0350002be0) at ../../module/zfs/zio.c:2659 /openzfs#486 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1399 /openzfs#487 zio_nowait (zio=0x7f0350002be0) at ../../module/zfs/zio.c:1456 /openzfs#488 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350002810) at ../../module/zfs/vdev_mirror.c:374 /openzfs#489 0x00007f03c807f243 in __zio_execute (zio=0x7f0350002810) at ../../module/zfs/zio.c:1399 /openzfs#490 zio_nowait (zio=0x7f0350002810) at ../../module/zfs/zio.c:1456 /openzfs#491 0x00007f03c8064593 in vdev_raidz_io_start (zio=0x7f0350001270) at ../../module/zfs/vdev_raidz.c:1591 /openzfs#492 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001270) at ../../module/zfs/zio.c:1399 /openzfs#493 zio_nowait (zio=0x7f0350001270) at ../../module/zfs/zio.c:1456 /openzfs#494 0x00007f03c805f71b in vdev_mirror_io_start (zio=0x7f0350001e60) at ../../module/zfs/vdev_mirror.c:374 /openzfs#495 0x00007f03c807f243 in __zio_execute (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1399 /openzfs#496 zio_nowait (zio=0x7f0350001e60) at ../../module/zfs/zio.c:1456 /openzfs#497 0x00007f03c805ed43 in vdev_mirror_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/vdev_mirror.c:499 /openzfs#498 0x00007f03c807a0c0 in zio_vdev_io_done (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:2707 /openzfs#499 0x00007f03c808285b in __zio_execute (zio=0x7f033a0c39c0) at ../../module/zfs/zio.c:1399 /openzfs#500 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f03a8003c00, pio=0x7f033a0c39c0) at ../../module/zfs/zio.c:547 /openzfs#501 zio_done (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:3278 /openzfs#502 0x00007f03c808285b in __zio_execute (zio=0x7f03a8003c00) at ../../module/zfs/zio.c:1399 /openzfs#503 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800c400, pio=0x7f03a8003c00) at ../../module/zfs/zio.c:547 /openzfs#504 zio_done (zio=0x7f038800c400) at ../../module/zfs/zio.c:3278 /openzfs#505 0x00007f03c808285b in __zio_execute (zio=0x7f038800c400) at ../../module/zfs/zio.c:1399 /openzfs#506 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800da00, pio=0x7f038800c400) at ../../module/zfs/zio.c:547 /openzfs#507 zio_done (zio=0x7f038800da00) at ../../module/zfs/zio.c:3278 /openzfs#508 0x00007f03c808285b in __zio_execute (zio=0x7f038800da00) at ../../module/zfs/zio.c:1399 /openzfs#509 zio_notify_parent (wait=ZIO_WAIT_DONE, zio=0x7f038800fd80, pio=0x7f038800da00) at ../../module/zfs/zio.c:547 /openzfs#510 zio_done (zio=0x7f038800fd80) at ../../module/zfs/zio.c:3278 /openzfs#511 0x00007f03c807a6d3 in __zio_execute (zio=0x7f038800fd80) at ../../module/zfs/zio.c:1399 /openzfs#512 zio_execute (zio=zio@entry=0x7f038800fd80) at ../../module/zfs/zio.c:1337 /openzfs#513 0x00007f03c8060b35 in vdev_queue_io_to_issue (vq=vq@entry=0x99f8a8) at ../../module/zfs/vdev_queue.c:706 /openzfs#514 0x00007f03c806119d in vdev_queue_io_done (zio=zio@entry=0x7f03a0010950) at ../../module/zfs/vdev_queue.c:775 /openzfs#515 0x00007f03c807a0e8 in zio_vdev_io_done (zio=0x7f03a0010950) at ../../module/zfs/zio.c:2686 /openzfs#516 0x00007f03c807a6d3 in __zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1399 /openzfs#517 zio_execute (zio=0x7f03a0010950) at ../../module/zfs/zio.c:1337 /openzfs#518 0x00007f03c7fcd0c4 in taskq_thread (arg=0x966d50) at ../../lib/libzpool/taskq.c:215 /openzfs#519 0x00007f03c7fc7937 in zk_thread_helper (arg=0x967e90) at ../../lib/libzpool/kernel.c:135 /openzfs#520 0x00007f03c78890a3 in start_thread (arg=0x7f03c2703700) at pthread_create.c:309 /openzfs#521 0x00007f03c75c50fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 This occurred when ztest was simulating a scrub under heavy I/O load. Under those circumstances, it was possible for a mix of noop I/Os for aggregation continuity and the I/O elevator to generate arbitrarily deep recursion. This patch modifies ZFS to propapage a recursion counter inside the zio_t objects such that IOs will be redispatched upon reaching a given recursion depth. We can detect long call chains and dispatch to another ZIO taskq. We cut in-line when we do this to minimize the potential for taskq exhaustion that can prevent a zio from notifying its parent. Signed-off-by: Richard Yao <ryao@gentoo.org>
behlendorf
pushed a commit
to behlendorf/zfs
that referenced
this issue
May 21, 2018
Currently taskq_dispatch() will spawn new task with a condition that the caller is also a member of the taskq. However, under this condition, it will still cause deadlock where a task on tq1 is waiting another thread, who is trying to dispatch a task on tq1. So this patch removes the check. For example when you do: zfs send pp/fs0@001 | zfs recv pp/fs0_copy This will easily deadlock before this patch. Also, move the seq_task check from taskq_thread_spawn() to taskq_thread() because it's not used by the caller from taskq_dispatch(). Signed-off-by: Chunwei Chen <david.chen@osnexus.com> Signed-off-by: Tim Chase <tim@chase2k.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes openzfs#496
pcd1193182
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Sep 26, 2023
…aster Merge remote-tracking branch '6.0/stage' into 'master'
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After ZFS running smoothly after I reverted to a 3.0 kernel and limited the ARC size to 2GB (1/8th of memory), I got a lock up this morning.
At the time, there was a rsync going on from a remote machine onto a 6TiB ext4 FS mounted on top of a sparse zvol (with compression), and a ddrescue running on remote host onto a zvol served over nbd (nbd-server exporting the zvol) again with
compression and with a block size of 4kiB.
At the time, ddrescue was dumping zeros so highly compressable data.
Hold on, another similar lockup again after I've rebooted it and resumed the ddrescue. This time, no rsync running, just the
nbd-server, but it booted into 3.1.4 (my mistake). Here is some serial console capture (on the first occurrence)
The text was updated successfully, but these errors were encountered: