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author | Duoming Zhou <duoming@zju.edu.cn> | 2022-04-17 17:16:41 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-14 19:32:42 +0300 |
commit | 0f69d7d5e918aa43423d86bd17ddb11b1b5e8ada (patch) | |
tree | 7d3781329d6841b84a2195e7998b20c29fa12c26 /drivers/staging | |
parent | 66f769762f65d957f688f3258755c6ec410bf710 (diff) | |
download | linux-0f69d7d5e918aa43423d86bd17ddb11b1b5e8ada.tar.xz |
drivers: staging: rtl8192e: Fix deadlock in rtllib_beacons_stop()
[ Upstream commit 9b6bdbd9337de3917945847bde262a34a87a6303 ]
There is a deadlock in rtllib_beacons_stop(), which is shown
below:
(Thread 1) | (Thread 2)
| rtllib_send_beacon()
rtllib_beacons_stop() | mod_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | rtllib_send_beacon_cb()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold ieee->beacon_lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need ieee->beacon_lock in position (2) of thread 2.
As a result, rtllib_beacons_stop() will block forever.
This patch extracts del_timer_sync() from the protection of
spin_lock_irqsave(), which could let timer handler to obtain
the needed lock.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220417141641.124388-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/staging')
-rw-r--r-- | drivers/staging/rtl8192e/rtllib_softmac.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/staging/rtl8192e/rtllib_softmac.c b/drivers/staging/rtl8192e/rtllib_softmac.c index e8e72f79ca00..aeb6f015fdda 100644 --- a/drivers/staging/rtl8192e/rtllib_softmac.c +++ b/drivers/staging/rtl8192e/rtllib_softmac.c @@ -651,9 +651,9 @@ static void rtllib_beacons_stop(struct rtllib_device *ieee) spin_lock_irqsave(&ieee->beacon_lock, flags); ieee->beacon_txing = 0; - del_timer_sync(&ieee->beacon_timer); spin_unlock_irqrestore(&ieee->beacon_lock, flags); + del_timer_sync(&ieee->beacon_timer); } |