From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 148ED7F for ; Tue, 7 Jun 2022 17:50:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CD20C34115; Tue, 7 Jun 2022 17:50:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624205; bh=iBHXIOeiRVVBCYsNK7bbGrVtLssRBgvab2AS9555VOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dHtcMydmV0YrSBB3YK0pPrF7IKKPHRFCGKJ+NaKr72ypz2DjK/5CVkTbMrHfUHK1B PvJyNBNFgkY5T396yAOTOuuH1duNcMJjXi9dEa+JDTXhScZ7Xfn6JFZa07iaJZaLga FutKE4zwvJJ6xVpf1NaOWzGrXE8NfDXWMfElkI7vVnYy0j312jPrFOx3ch5dHxBc7d L+uf1VsVIpp1HPDJJjbIhmMqI3Ef6sHSsqP/eTvaXz8yiEQ60sjPxQ6q0btL29cyU0 tiz7i8Qn5G43/izNpsdswuOMQKi1oUxy1sxHYL8HQPLClB9AmpGGhHKWBTuNNyU1Co KVdWmVBg3k+7g== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Duoming Zhou , Greg Kroah-Hartman , Sasha Levin , baihaowen@meizu.com, dan.carpenter@oracle.com, wjsota@gmail.com, len.baker@gmx.com, dave@stgolabs.net, edumazet@google.com, yangyingliang@huawei.com, linux-staging@lists.linux.dev Subject: [PATCH AUTOSEL 5.18 12/68] drivers: staging: rtl8192e: Fix deadlock in rtllib_beacons_stop() Date: Tue, 7 Jun 2022 13:47:38 -0400 Message-Id: <20220607174846.477972-12-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607174846.477972-1-sashal@kernel.org> References: <20220607174846.477972-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Duoming Zhou [ 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 Link: https://lore.kernel.org/r/20220417141641.124388-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- 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 4b6c2295a3cf..b5a38f0a8d79 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); } -- 2.35.1