From nobody Mon May 11 02:57:21 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 269D3C433F5 for ; Sun, 17 Apr 2022 14:21:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234227AbiDQOTn (ORCPT ); Sun, 17 Apr 2022 10:19:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229496AbiDQOTk (ORCPT ); Sun, 17 Apr 2022 10:19:40 -0400 Received: from zju.edu.cn (mail.zju.edu.cn [61.164.42.155]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id BE86937A0F for ; Sun, 17 Apr 2022 07:17:03 -0700 (PDT) Received: from ubuntu.localdomain (unknown [10.15.192.164]) by mail-app3 (Coremail) with SMTP id cC_KCgA35vFMIVxilmFcAg--.13118S2; Sun, 17 Apr 2022 22:16:53 +0800 (CST) From: Duoming Zhou To: linux-kernel@vger.kernel.org Cc: linux-staging@lists.linux.dev, akpm@linux-foundation.org, broonie@kernel.org, alexander.deucher@amd.com, davem@davemloft.net, gregkh@linuxfoundation.org, Duoming Zhou Subject: [PATCH] drivers: staging: rtl8192e: Fix deadlock in rtllib_beacons_stop() Date: Sun, 17 Apr 2022 22:16:41 +0800 Message-Id: <20220417141641.124388-1-duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: cC_KCgA35vFMIVxilmFcAg--.13118S2 X-Coremail-Antispam: 1UD129KBjvJXoW7uF4xuw4rZF48urWfAF13Arb_yoW8Gw4rpF WDWFy3AF1jvr48ua4jyw4kZryfCw42vrWDuayakw4rZ3Z7XFy5XF1jyFWYkF45JFZrtw13 AFn5Z3y5uFn0k3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUka1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2 z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcV Aq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1Y 6r17McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64 vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxAIw28IcxkI7VAKI48JMxAIw28IcVCjz48v 1sIEY20_GFWkJr1UJwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r 18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vI r41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr 1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvE x4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUkrcfUUUUU= X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAgoDAVZdtZOq7gASsx Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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 --- 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/rt= l8192e/rtllib_softmac.c index 4b6c2295a3c..b5a38f0a8d7 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 *i= eee) spin_lock_irqsave(&ieee->beacon_lock, flags); =20 ieee->beacon_txing =3D 0; - del_timer_sync(&ieee->beacon_timer); =20 spin_unlock_irqrestore(&ieee->beacon_lock, flags); + del_timer_sync(&ieee->beacon_timer); =20 } =20 --=20 2.17.1