| Message ID | b2c4acc1802ce879cfc4b57efa7dbc1619a0a009.1649310812.git.duoming@zju.edu.cn |
|---|---|
| State | New |
| Headers | show |
| Series | Fix deadlocks caused by del_timer_sync() | expand |
diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme.c b/drivers/staging/rtl8723bs/core/rtw_mlme.c index d559eefe633..5030556929d 100644 --- a/drivers/staging/rtl8723bs/core/rtw_mlme.c +++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c @@ -1240,8 +1240,10 @@ void rtw_joinbss_event_prehandle(struct adapter *adapter, u8 *pbuf) spin_unlock_bh(&pmlmepriv->scanned_queue.lock); + spin_unlock_bh(&pmlmepriv->lock); /* s5. Cancel assoc_timer */ del_timer_sync(&pmlmepriv->assoc_timer); + spin_lock_bh(&pmlmepriv->lock); } else { spin_unlock_bh(&(pmlmepriv->scanned_queue.lock)); }
There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_joinbss_event_prehandle()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | _rtw_join_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_joinbss_event_prehandle() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- drivers/staging/rtl8723bs/core/rtw_mlme.c | 2 ++ 1 file changed, 2 insertions(+)