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| author | Duoming Zhou <duoming@zju.edu.cn> | 2022-04-09 10:21:35 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-13 09:50:38 +0300 |
| commit | 0fcddf9c7c10202946d5b19409efbdff744fba88 (patch) | |
| tree | b647b3c622d2a38fd3ea218dadbe5a4c4790102f | |
| parent | 041879b12ddb0c6c83ed9c0bdd10dc82a056f2fc (diff) | |
| download | linux-0fcddf9c7c10202946d5b19409efbdff744fba88.tar.xz | |
drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle
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()
| _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. What`s more, we change spin_lock_bh() to
spin_lock_irq() in _rtw_join_timeout_handler() in order to
prevent deadlock.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220409072135.74248-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/r8188eu/core/rtw_mlme.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/staging/r8188eu/core/rtw_mlme.c b/drivers/staging/r8188eu/core/rtw_mlme.c index aa39f07847c2..3e9882f89f76 100644 --- a/drivers/staging/r8188eu/core/rtw_mlme.c +++ b/drivers/staging/r8188eu/core/rtw_mlme.c @@ -1070,8 +1070,10 @@ void rtw_joinbss_event_prehandle(struct adapter *adapter, u8 *pbuf) rtw_indicate_connect(adapter); } + 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); goto ignore_joinbss_callback; @@ -1315,7 +1317,7 @@ void _rtw_join_timeout_handler (struct adapter *adapter) if (adapter->bDriverStopped || adapter->bSurpriseRemoved) return; - spin_lock_bh(&pmlmepriv->lock); + spin_lock_irq(&pmlmepriv->lock); if (rtw_to_roaming(adapter) > 0) { /* join timeout caused by roaming */ while (1) { @@ -1334,7 +1336,7 @@ void _rtw_join_timeout_handler (struct adapter *adapter) rtw_indicate_disconnect(adapter); free_scanqueue(pmlmepriv);/* */ } - spin_unlock_bh(&pmlmepriv->lock); + spin_unlock_irq(&pmlmepriv->lock); } |