From: Duoming Zhou <duoming@zju.edu.cn> stable inclusion from stable-v4.19.247 commit 08bacf871c019163ccd1389d0bc957a43324967a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBP731 CVE: CVE-2022-49315 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> --- drivers/staging/rtl8192e/rtllib_softmac.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/staging/rtl8192e/rtllib_softmac.c b/drivers/staging/rtl8192e/rtllib_softmac.c index 919231fec09c..5f1dd4e2d12e 100644 --- a/drivers/staging/rtl8192e/rtllib_softmac.c +++ b/drivers/staging/rtl8192e/rtllib_softmac.c @@ -654,9 +654,9 @@ 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); } -- 2.25.1