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Aborting when before_wait function panics
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raoulstrackx committed Aug 1, 2023
1 parent 9a5443f commit 9baab45
Showing 1 changed file with 10 additions and 6 deletions.
16 changes: 10 additions & 6 deletions library/std/src/sys/sgx/waitqueue/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ mod unsafe_list;

use crate::num::NonZeroUsize;
use crate::ops::{Deref, DerefMut};
use crate::panic::{self, AssertUnwindSafe};
use crate::time::Duration;

use super::abi::thread;
Expand Down Expand Up @@ -147,9 +148,8 @@ impl WaitQueue {
/// Adds the calling thread to the `WaitVariable`'s wait queue, then wait
/// until a wakeup event.
///
/// This function does not return until this thread has been awoken.
///
/// Safety: `before_wait` must not panic
/// This function does not return until this thread has been awoken. When `before_wait` panics,
/// this function will abort.
pub fn wait<T, F: FnOnce()>(mut guard: SpinMutexGuard<'_, WaitVariable<T>>, before_wait: F) {
// very unsafe: check requirements of UnsafeList::push
unsafe {
Expand All @@ -159,7 +159,9 @@ impl WaitQueue {
}));
let entry = guard.queue.inner.push(&mut entry);
drop(guard);
before_wait();
if let Err(_e) = panic::catch_unwind(AssertUnwindSafe(|| before_wait())) {
rtabort!("Panic before wait on wakeup event")
}
while !entry.lock().wake {
// `entry.wake` is only set in `notify_one` and `notify_all` functions. Both ensure
// the entry is removed from the queue _before_ setting this bool. There are no
Expand All @@ -174,7 +176,7 @@ impl WaitQueue {
/// Adds the calling thread to the `WaitVariable`'s wait queue, then wait
/// until a wakeup event or timeout. If event was observed, returns true.
/// If not, it will remove the calling thread from the wait queue.
/// Safety: `before_wait` must not panic
/// When `before_wait` panics, this function will abort.
pub fn wait_timeout<T, F: FnOnce()>(
lock: &SpinMutex<WaitVariable<T>>,
timeout: Duration,
Expand All @@ -187,7 +189,9 @@ impl WaitQueue {
wake: false,
}));
let entry_lock = lock.lock().queue.inner.push(&mut entry);
before_wait();
if let Err(_e) = panic::catch_unwind(AssertUnwindSafe(|| before_wait())) {
rtabort!("Panic before wait on wakeup event or timeout")
}
usercalls::wait_timeout(EV_UNPARK, timeout, || entry_lock.lock().wake);
// acquire the wait queue's lock first to avoid deadlock
// and ensure no other function can simultaneously access the list
Expand Down

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