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staging: rtl8723bs: remove possible deadlock when disconnect (v2)
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when turning off a connection, lockdep complains with the
following warning (a modprobe has been done but the same
happens with a disconnection from NetworkManager,
it's enough to trigger a cfg80211_disconnect call):

[  682.855867] ======================================================
[  682.855877] WARNING: possible circular locking dependency detected
[  682.855887] 5.14.0-rc6+ #16 Tainted: G         C OE
[  682.855898] ------------------------------------------------------
[  682.855906] modprobe/1770 is trying to acquire lock:
[  682.855916] ffffb6d000332b00 (&pxmitpriv->lock){+.-.}-{2:2},
		at: rtw_free_stainfo+0x52/0x4a0 [r8723bs]
[  682.856073]
               but task is already holding lock:
[  682.856081] ffffb6d0003336a8 (&pstapriv->sta_hash_lock){+.-.}-{2:2},
		at: rtw_free_assoc_resources+0x48/0x110 [r8723bs]
[  682.856207]
               which lock already depends on the new lock.

[  682.856215]
               the existing dependency chain (in reverse order) is:
[  682.856223]
               -> #1 (&pstapriv->sta_hash_lock){+.-.}-{2:2}:
[  682.856247]        _raw_spin_lock_bh+0x34/0x40
[  682.856265]        rtw_get_stainfo+0x9a/0x110 [r8723bs]
[  682.856389]        rtw_xmit_classifier+0x27/0x130 [r8723bs]
[  682.856515]        rtw_xmitframe_enqueue+0xa/0x20 [r8723bs]
[  682.856642]        rtl8723bs_hal_xmit+0x3b/0xb0 [r8723bs]
[  682.856752]        rtw_xmit+0x4ef/0x890 [r8723bs]
[  682.856879]        _rtw_xmit_entry+0xba/0x350 [r8723bs]
[  682.856981]        dev_hard_start_xmit+0xee/0x320
[  682.856999]        sch_direct_xmit+0x8c/0x330
[  682.857014]        __dev_queue_xmit+0xba5/0xf00
[  682.857030]        packet_sendmsg+0x981/0x1b80
[  682.857047]        sock_sendmsg+0x5b/0x60
[  682.857060]        __sys_sendto+0xf1/0x160
[  682.857073]        __x64_sys_sendto+0x24/0x30
[  682.857087]        do_syscall_64+0x3a/0x80
[  682.857102]        entry_SYSCALL_64_after_hwframe+0x44/0xae
[  682.857117]
               -> #0 (&pxmitpriv->lock){+.-.}-{2:2}:
[  682.857142]        __lock_acquire+0xfd9/0x1b50
[  682.857158]        lock_acquire+0xb4/0x2c0
[  682.857172]        _raw_spin_lock_bh+0x34/0x40
[  682.857185]        rtw_free_stainfo+0x52/0x4a0 [r8723bs]
[  682.857308]        rtw_free_assoc_resources+0x53/0x110 [r8723bs]
[  682.857415]        cfg80211_rtw_disconnect+0x4b/0x70 [r8723bs]
[  682.857522]        cfg80211_disconnect+0x12e/0x2f0 [cfg80211]
[  682.857759]        cfg80211_leave+0x2b/0x40 [cfg80211]
[  682.857961]        cfg80211_netdev_notifier_call+0xa9/0x560 [cfg80211]
[  682.858163]        raw_notifier_call_chain+0x41/0x50
[  682.858180]        __dev_close_many+0x62/0x100
[  682.858195]        dev_close_many+0x7d/0x120
[  682.858209]        unregister_netdevice_many+0x416/0x680
[  682.858225]        unregister_netdevice_queue+0xab/0xf0
[  682.858240]        unregister_netdev+0x18/0x20
[  682.858255]        rtw_unregister_netdevs+0x28/0x40 [r8723bs]
[  682.858360]        rtw_dev_remove+0x24/0xd0 [r8723bs]
[  682.858463]        sdio_bus_remove+0x31/0xd0 [mmc_core]
[  682.858532]        device_release_driver_internal+0xf7/0x1d0
[  682.858550]        driver_detach+0x47/0x90
[  682.858564]        bus_remove_driver+0x77/0xd0
[  682.858579]        rtw_drv_halt+0xc/0x678 [r8723bs]
[  682.858685]        __x64_sys_delete_module+0x13f/0x250
[  682.858699]        do_syscall_64+0x3a/0x80
[  682.858715]        entry_SYSCALL_64_after_hwframe+0x44/0xae
[  682.858729]
               other info that might help us debug this:

[  682.858737]  Possible unsafe locking scenario:

[  682.858744]        CPU0                    CPU1
[  682.858751]        ----                    ----
[  682.858758]   lock(&pstapriv->sta_hash_lock);
[  682.858772]                                lock(&pxmitpriv->lock);
[  682.858786]                                lock(&pstapriv->sta_hash_lock);
[  682.858799]   lock(&pxmitpriv->lock);
[  682.858812]
                *** DEADLOCK ***

[  682.858820] 5 locks held by modprobe/1770:
[  682.858831]  #0: ffff8d870697d980 (&dev->mutex){....}-{3:3},
		at: device_release_driver_internal+0x1a/0x1d0
[  682.858869]  #1: ffffffffbdbbf1c8 (rtnl_mutex){+.+.}-{3:3},
		at: unregister_netdev+0xe/0x20
[  682.858906]  #2: ffff8d87054ee5e8 (&rdev->wiphy.mtx){+.+.}-{3:3},
		at: cfg80211_netdev_notifier_call+0x9e/0x560 [cfg80211]
[  682.859131]  #3: ffff8d870f2bc8f0 (&wdev->mtx){+.+.}-{3:3},
		at: cfg80211_leave+0x20/0x40 [cfg80211]
[  682.859354]  #4: ffffb6d0003336a8 (&pstapriv->sta_hash_lock){+.-.}-{2:2},
		at: rtw_free_assoc_resources+0x48/0x110 [r8723bs]
[  682.859482]
               stack backtrace:
[  682.859491] CPU: 1 PID: 1770 Comm: modprobe Tainted: G
		C OE     5.14.0-rc6+ #16
[  682.859507] Hardware name: LENOVO 80NR/Madrid, BIOS DACN25WW 08/20/2015
[  682.859517] Call Trace:
[  682.859531]  dump_stack_lvl+0x56/0x6f
[  682.859551]  check_noncircular+0xdb/0xf0
[  682.859579]  __lock_acquire+0xfd9/0x1b50
[  682.859606]  lock_acquire+0xb4/0x2c0
[  682.859623]  ? rtw_free_stainfo+0x52/0x4a0 [r8723bs]
[  682.859752]  ? mark_held_locks+0x48/0x70
[  682.859769]  ? rtw_free_stainfo+0x4a/0x4a0 [r8723bs]
[  682.859898]  _raw_spin_lock_bh+0x34/0x40
[  682.859914]  ? rtw_free_stainfo+0x52/0x4a0 [r8723bs]
[  682.860039]  rtw_free_stainfo+0x52/0x4a0 [r8723bs]
[  682.860171]  rtw_free_assoc_resources+0x53/0x110 [r8723bs]
[  682.860286]  cfg80211_rtw_disconnect+0x4b/0x70 [r8723bs]
[  682.860397]  cfg80211_disconnect+0x12e/0x2f0 [cfg80211]
[  682.860629]  cfg80211_leave+0x2b/0x40 [cfg80211]
[  682.860836]  cfg80211_netdev_notifier_call+0xa9/0x560 [cfg80211]
[  682.861048]  ? __lock_acquire+0x4dc/0x1b50
[  682.861070]  ? lock_is_held_type+0xa8/0x110
[  682.861089]  ? lock_is_held_type+0xa8/0x110
[  682.861104]  ? find_held_lock+0x2d/0x90
[  682.861120]  ? packet_notifier+0x173/0x300
[  682.861141]  ? lock_release+0xb3/0x250
[  682.861160]  ? packet_notifier+0x192/0x300
[  682.861184]  raw_notifier_call_chain+0x41/0x50
[  682.861205]  __dev_close_many+0x62/0x100
[  682.861224]  dev_close_many+0x7d/0x120
[  682.861245]  unregister_netdevice_many+0x416/0x680
[  682.861264]  ? find_held_lock+0x2d/0x90
[  682.861284]  unregister_netdevice_queue+0xab/0xf0
[  682.861306]  unregister_netdev+0x18/0x20
[  682.861325]  rtw_unregister_netdevs+0x28/0x40 [r8723bs]
[  682.861434]  rtw_dev_remove+0x24/0xd0 [r8723bs]
[  682.861542]  sdio_bus_remove+0x31/0xd0 [mmc_core]
[  682.861615]  device_release_driver_internal+0xf7/0x1d0
[  682.861637]  driver_detach+0x47/0x90
[  682.861656]  bus_remove_driver+0x77/0xd0
[  682.861674]  rtw_drv_halt+0xc/0x678 [r8723bs]
[  682.861782]  __x64_sys_delete_module+0x13f/0x250
[  682.861801]  ? lockdep_hardirqs_on_prepare+0xf3/0x170
[  682.861817]  ? syscall_enter_from_user_mode+0x20/0x70
[  682.861836]  do_syscall_64+0x3a/0x80
[  682.861855]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  682.861873] RIP: 0033:0x7f6dbe85400b
[  682.861890] Code: 73 01 c3 48 8b 0d 6d 1e 0c 00 f7 d8 64 89
01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa
b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 3d
1e 0c 00 f7 d8 64 89 01 48
[  682.861906] RSP: 002b:00007ffe7a82f538 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
[  682.861923] RAX: ffffffffffffffda RBX: 000055a64693bd20 RCX: 00007f6dbe85400b
[  682.861935] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055a64693bd88
[  682.861946] RBP: 000055a64693bd20 R08: 0000000000000000 R09: 0000000000000000
[  682.861957] R10: 00007f6dbe8c7ac0 R11: 0000000000000206 R12: 000055a64693bd88
[  682.861967] R13: 0000000000000000 R14: 000055a64693bd88 R15: 00007ffe7a831848

This happens because when we enqueue a frame for
transmission we do it under xmit_priv lock, then calling
rtw_get_stainfo (needed for enqueuing) takes sta_hash_lock
and this leads to the following lock dependency:

xmit_priv->lock -> sta_hash_lock

Turning off a connection will bring to call
rtw_free_assoc_resources which will set up
the inverse dependency:

sta_hash_lock -> xmit_priv_lock

This could lead to a deadlock as lockdep complains.

Fix it by removing the xmit_priv->lock around
rtw_xmitframe_enqueue call inside rtl8723bs_hal_xmit
and put it in a smaller critical section inside
rtw_xmit_classifier, the only place where
xmit_priv data are actually accessed.

Replace spin_{lock,unlock}_bh(pxmitpriv->lock)
in other tx paths leading to rtw_xmitframe_enqueue
call with spin_{lock,unlock}_bh(psta->sleep_q.lock)
- it's not clear why accessing a sleep_q was protected
by a spinlock on xmitpriv->lock.

This way is avoided the same faulty lock nesting
order.

Extra changes in v2 by Hans de Goede:
-Lift the taking of the struct __queue.lock spinlock out of
 rtw_free_xmitframe_queue() into the callers this allows also
 protecting a bunch of related state in rtw_free_stainfo():
-Protect psta->sleepq_len on rtw_free_xmitframe_queue(&psta->sleep_q);
-Protect struct tx_servq.tx_pending and tx_servq.qcnt when
 calling rtw_free_xmitframe_queue(&tx_servq.sta_pending)
-This also allows moving the spin_lock_bh(&pxmitpriv->lock); to below
 the sleep_q free-ing code, avoiding another ABBA locking issue

CC: Larry Finger <Larry.Finger@lwfinger.net>
Co-developed-by: Hans de Goede <hdegoede@redhat.com>
Tested-on: Lenovo Ideapad MiiX 300-10IBY
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210920145502.155454-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@fabioaiuto @gregkh
fabioaiuto authored and gregkh committed Sep 21, 2021
1 parent 7bdedfe commit 54659ca
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Showing 5 changed files with 24 additions and 33 deletions.
7 changes: 2 additions & 5 deletions drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5919,7 +5919,6 @@ u8 chk_bmc_sleepq_hdl(struct adapter *padapter, unsigned char *pbuf)
struct sta_info *psta_bmc;
struct list_head *xmitframe_plist, *xmitframe_phead, *tmp;
struct xmit_frame *pxmitframe = NULL;
struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
struct sta_priv *pstapriv = &padapter->stapriv;

/* for BC/MC Frames */
Expand All @@ -5930,8 +5929,7 @@ u8 chk_bmc_sleepq_hdl(struct adapter *padapter, unsigned char *pbuf)
if ((pstapriv->tim_bitmap&BIT(0)) && (psta_bmc->sleepq_len > 0)) {
msleep(10);/* 10ms, ATIM(HIQ) Windows */

/* spin_lock_bh(&psta_bmc->sleep_q.lock); */
spin_lock_bh(&pxmitpriv->lock);
spin_lock_bh(&psta_bmc->sleep_q.lock);

xmitframe_phead = get_list_head(&psta_bmc->sleep_q);
list_for_each_safe(xmitframe_plist, tmp, xmitframe_phead) {
Expand All @@ -5954,8 +5952,7 @@ u8 chk_bmc_sleepq_hdl(struct adapter *padapter, unsigned char *pbuf)
rtw_hal_xmitframe_enqueue(padapter, pxmitframe);
}

/* spin_unlock_bh(&psta_bmc->sleep_q.lock); */
spin_unlock_bh(&pxmitpriv->lock);
spin_unlock_bh(&psta_bmc->sleep_q.lock);

/* check hi queue and bmc_sleepq */
rtw_chk_hi_queue_cmd(padapter);
Expand Down
10 changes: 3 additions & 7 deletions drivers/staging/rtl8723bs/core/rtw_recv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -957,10 +957,8 @@ static signed int validate_recv_ctrl_frame(struct adapter *padapter, union recv_
if ((psta->state&WIFI_SLEEP_STATE) && (pstapriv->sta_dz_bitmap&BIT(psta->aid))) {
struct list_head *xmitframe_plist, *xmitframe_phead;
struct xmit_frame *pxmitframe = NULL;
struct xmit_priv *pxmitpriv = &padapter->xmitpriv;

/* spin_lock_bh(&psta->sleep_q.lock); */
spin_lock_bh(&pxmitpriv->lock);
spin_lock_bh(&psta->sleep_q.lock);

xmitframe_phead = get_list_head(&psta->sleep_q);
xmitframe_plist = get_next(xmitframe_phead);
Expand Down Expand Up @@ -991,12 +989,10 @@ static signed int validate_recv_ctrl_frame(struct adapter *padapter, union recv_
update_beacon(padapter, WLAN_EID_TIM, NULL, true);
}

/* spin_unlock_bh(&psta->sleep_q.lock); */
spin_unlock_bh(&pxmitpriv->lock);
spin_unlock_bh(&psta->sleep_q.lock);

} else {
/* spin_unlock_bh(&psta->sleep_q.lock); */
spin_unlock_bh(&pxmitpriv->lock);
spin_unlock_bh(&psta->sleep_q.lock);

if (pstapriv->tim_bitmap&BIT(psta->aid)) {
if (psta->sleepq_len == 0) {
Expand Down
22 changes: 12 additions & 10 deletions drivers/staging/rtl8723bs/core/rtw_sta_mgt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -294,46 +294,48 @@ u32 rtw_free_stainfo(struct adapter *padapter, struct sta_info *psta)

/* list_del_init(&psta->wakeup_list); */

spin_lock_bh(&pxmitpriv->lock);

spin_lock_bh(&psta->sleep_q.lock);
rtw_free_xmitframe_queue(pxmitpriv, &psta->sleep_q);
psta->sleepq_len = 0;
spin_unlock_bh(&psta->sleep_q.lock);

spin_lock_bh(&pxmitpriv->lock);

/* vo */
/* spin_lock_bh(&(pxmitpriv->vo_pending.lock)); */
spin_lock_bh(&pstaxmitpriv->vo_q.sta_pending.lock);
rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->vo_q.sta_pending);
list_del_init(&(pstaxmitpriv->vo_q.tx_pending));
phwxmit = pxmitpriv->hwxmits;
phwxmit->accnt -= pstaxmitpriv->vo_q.qcnt;
pstaxmitpriv->vo_q.qcnt = 0;
/* spin_unlock_bh(&(pxmitpriv->vo_pending.lock)); */
spin_unlock_bh(&pstaxmitpriv->vo_q.sta_pending.lock);

/* vi */
/* spin_lock_bh(&(pxmitpriv->vi_pending.lock)); */
spin_lock_bh(&pstaxmitpriv->vi_q.sta_pending.lock);
rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->vi_q.sta_pending);
list_del_init(&(pstaxmitpriv->vi_q.tx_pending));
phwxmit = pxmitpriv->hwxmits+1;
phwxmit->accnt -= pstaxmitpriv->vi_q.qcnt;
pstaxmitpriv->vi_q.qcnt = 0;
/* spin_unlock_bh(&(pxmitpriv->vi_pending.lock)); */
spin_unlock_bh(&pstaxmitpriv->vi_q.sta_pending.lock);

/* be */
/* spin_lock_bh(&(pxmitpriv->be_pending.lock)); */
spin_lock_bh(&pstaxmitpriv->be_q.sta_pending.lock);
rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->be_q.sta_pending);
list_del_init(&(pstaxmitpriv->be_q.tx_pending));
phwxmit = pxmitpriv->hwxmits+2;
phwxmit->accnt -= pstaxmitpriv->be_q.qcnt;
pstaxmitpriv->be_q.qcnt = 0;
/* spin_unlock_bh(&(pxmitpriv->be_pending.lock)); */
spin_unlock_bh(&pstaxmitpriv->be_q.sta_pending.lock);

/* bk */
/* spin_lock_bh(&(pxmitpriv->bk_pending.lock)); */
spin_lock_bh(&pstaxmitpriv->bk_q.sta_pending.lock);
rtw_free_xmitframe_queue(pxmitpriv, &pstaxmitpriv->bk_q.sta_pending);
list_del_init(&(pstaxmitpriv->bk_q.tx_pending));
phwxmit = pxmitpriv->hwxmits+3;
phwxmit->accnt -= pstaxmitpriv->bk_q.qcnt;
pstaxmitpriv->bk_q.qcnt = 0;
/* spin_unlock_bh(&(pxmitpriv->bk_pending.lock)); */
spin_unlock_bh(&pstaxmitpriv->bk_q.sta_pending.lock);

spin_unlock_bh(&pxmitpriv->lock);

Expand Down
16 changes: 7 additions & 9 deletions drivers/staging/rtl8723bs/core/rtw_xmit.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1734,15 +1734,12 @@ void rtw_free_xmitframe_queue(struct xmit_priv *pxmitpriv, struct __queue *pfram
struct list_head *plist, *phead, *tmp;
struct xmit_frame *pxmitframe;

spin_lock_bh(&pframequeue->lock);

phead = get_list_head(pframequeue);
list_for_each_safe(plist, tmp, phead) {
pxmitframe = list_entry(plist, struct xmit_frame, list);

rtw_free_xmitframe(pxmitpriv, pxmitframe);
}
spin_unlock_bh(&pframequeue->lock);
}

s32 rtw_xmitframe_enqueue(struct adapter *padapter, struct xmit_frame *pxmitframe)
Expand Down Expand Up @@ -1797,6 +1794,7 @@ s32 rtw_xmit_classifier(struct adapter *padapter, struct xmit_frame *pxmitframe)
struct sta_info *psta;
struct tx_servq *ptxservq;
struct pkt_attrib *pattrib = &pxmitframe->attrib;
struct xmit_priv *xmit_priv = &padapter->xmitpriv;
struct hw_xmit *phwxmits = padapter->xmitpriv.hwxmits;
signed int res = _SUCCESS;

Expand All @@ -1814,12 +1812,14 @@ s32 rtw_xmit_classifier(struct adapter *padapter, struct xmit_frame *pxmitframe)

ptxservq = rtw_get_sta_pending(padapter, psta, pattrib->priority, (u8 *)(&ac_index));

spin_lock_bh(&xmit_priv->lock);
if (list_empty(&ptxservq->tx_pending))
list_add_tail(&ptxservq->tx_pending, get_list_head(phwxmits[ac_index].sta_queue));

list_add_tail(&pxmitframe->list, get_list_head(&ptxservq->sta_pending));
ptxservq->qcnt++;
phwxmits[ac_index].accnt++;
spin_unlock_bh(&xmit_priv->lock);

exit:

Expand Down Expand Up @@ -2202,11 +2202,10 @@ void wakeup_sta_to_xmit(struct adapter *padapter, struct sta_info *psta)
struct list_head *xmitframe_plist, *xmitframe_phead, *tmp;
struct xmit_frame *pxmitframe = NULL;
struct sta_priv *pstapriv = &padapter->stapriv;
struct xmit_priv *pxmitpriv = &padapter->xmitpriv;

psta_bmc = rtw_get_bcmc_stainfo(padapter);

spin_lock_bh(&pxmitpriv->lock);
spin_lock_bh(&psta->sleep_q.lock);

xmitframe_phead = get_list_head(&psta->sleep_q);
list_for_each_safe(xmitframe_plist, tmp, xmitframe_phead) {
Expand Down Expand Up @@ -2307,7 +2306,7 @@ void wakeup_sta_to_xmit(struct adapter *padapter, struct sta_info *psta)

_exit:

spin_unlock_bh(&pxmitpriv->lock);
spin_unlock_bh(&psta->sleep_q.lock);

if (update_mask)
update_beacon(padapter, WLAN_EID_TIM, NULL, true);
Expand All @@ -2319,9 +2318,8 @@ void xmit_delivery_enabled_frames(struct adapter *padapter, struct sta_info *pst
struct list_head *xmitframe_plist, *xmitframe_phead, *tmp;
struct xmit_frame *pxmitframe = NULL;
struct sta_priv *pstapriv = &padapter->stapriv;
struct xmit_priv *pxmitpriv = &padapter->xmitpriv;

spin_lock_bh(&pxmitpriv->lock);
spin_lock_bh(&psta->sleep_q.lock);

xmitframe_phead = get_list_head(&psta->sleep_q);
list_for_each_safe(xmitframe_plist, tmp, xmitframe_phead) {
Expand Down Expand Up @@ -2374,7 +2372,7 @@ void xmit_delivery_enabled_frames(struct adapter *padapter, struct sta_info *pst
}
}

spin_unlock_bh(&pxmitpriv->lock);
spin_unlock_bh(&psta->sleep_q.lock);
}

void enqueue_pending_xmitbuf(struct xmit_priv *pxmitpriv, struct xmit_buf *pxmitbuf)
Expand Down
2 changes: 0 additions & 2 deletions drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -507,9 +507,7 @@ s32 rtl8723bs_hal_xmit(
rtw_issue_addbareq_cmd(padapter, pxmitframe);
}

spin_lock_bh(&pxmitpriv->lock);
err = rtw_xmitframe_enqueue(padapter, pxmitframe);
spin_unlock_bh(&pxmitpriv->lock);
if (err != _SUCCESS) {
rtw_free_xmitframe(pxmitpriv, pxmitframe);

Expand Down

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