[PATCH 5.15 237/371] drivers: staging: rtl8723bs: Fix locking in _rtw_join_timeout_handler()

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From: Hans de Goede <hdegoede@xxxxxxxxxx>

[ Upstream commit 215792eda008f6a1e7ed9d77fa20d582d22bb114 ]

Commit 041879b12ddb ("drivers: staging: rtl8192bs: Fix deadlock in
rtw_joinbss_event_prehandle()") besides fixing the deadlock also
modified _rtw_join_timeout_handler() to use spin_[un]lock_irq()
instead of spin_[un]lock_bh().

_rtw_join_timeout_handler() calls rtw_do_join() which takes
pmlmepriv->scanned_queue.lock using spin_[un]lock_bh(). This
spin_unlock_bh() call re-enables softirqs which triggers an oops in
kernel/softirq.c: __local_bh_enable_ip() when it calls
lockdep_assert_irqs_enabled():

[  244.506087] WARNING: CPU: 2 PID: 0 at kernel/softirq.c:376 __local_bh_enable_ip+0xa6/0x100
...
[  244.509022] Call Trace:
[  244.509048]  <IRQ>
[  244.509100]  _rtw_join_timeout_handler+0x134/0x170 [r8723bs]
[  244.509468]  ? __pfx__rtw_join_timeout_handler+0x10/0x10 [r8723bs]
[  244.509772]  ? __pfx__rtw_join_timeout_handler+0x10/0x10 [r8723bs]
[  244.510076]  call_timer_fn+0x95/0x2a0
[  244.510200]  __run_timers.part.0+0x1da/0x2d0

This oops is causd by the switch to spin_[un]lock_irq() which disables
the IRQs for the entire duration of _rtw_join_timeout_handler().

Disabling the IRQs is not necessary since all code taking this lock
runs from either user contexts or from softirqs, switch back to
spin_[un]lock_bh() to fix this.

Fixes: 041879b12ddb ("drivers: staging: rtl8192bs: Fix deadlock in rtw_joinbss_event_prehandle()")
Cc: Duoming Zhou <duoming@xxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230221145326.7808-1-hdegoede@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/staging/rtl8723bs/core/rtw_mlme.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme.c b/drivers/staging/rtl8723bs/core/rtw_mlme.c
index 26c40042d2bed..f85ef7dd61b24 100644
--- a/drivers/staging/rtl8723bs/core/rtw_mlme.c
+++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c
@@ -1547,7 +1547,7 @@ void _rtw_join_timeout_handler(struct timer_list *t)
 	if (adapter->bDriverStopped || adapter->bSurpriseRemoved)
 		return;
 
-	spin_lock_irq(&pmlmepriv->lock);
+	spin_lock_bh(&pmlmepriv->lock);
 
 	if (rtw_to_roam(adapter) > 0) { /* join timeout caused by roaming */
 		while (1) {
@@ -1575,7 +1575,7 @@ void _rtw_join_timeout_handler(struct timer_list *t)
 
 	}
 
-	spin_unlock_irq(&pmlmepriv->lock);
+	spin_unlock_bh(&pmlmepriv->lock);
 }
 
 /*
-- 
2.39.2






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