From nobody Thu Dec 18 07:54:20 2025 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 BC157C7EE32 for ; Tue, 23 May 2023 00:38:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235703AbjEWAiM (ORCPT ); Mon, 22 May 2023 20:38:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235186AbjEWAM4 (ORCPT ); Mon, 22 May 2023 20:12:56 -0400 Received: from zg8tmtyylji0my4xnjqumte4.icoremail.net (zg8tmtyylji0my4xnjqumte4.icoremail.net [162.243.164.118]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id F33C51FE7; Mon, 22 May 2023 16:59:45 -0700 (PDT) Received: from ubuntu.localdomain (unknown [218.12.18.192]) by mail-app4 (Coremail) with SMTP id cS_KCgAHPQjlAWxkmzJzAw--.47639S2; Tue, 23 May 2023 07:59:40 +0800 (CST) From: Duoming Zhou To: mchehab@kernel.org Cc: hverkuil-cisco@xs4all.nl, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Duoming Zhou Subject: [PATCH RESEND] media: usb: siano: Fix warning due to null work_func_t function pointer Date: Tue, 23 May 2023 07:59:32 +0800 Message-Id: <20230522235932.5927-1-duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: cS_KCgAHPQjlAWxkmzJzAw--.47639S2 X-Coremail-Antispam: 1UD129KBjvJXoWxAry8JFyDtFyDXrW5uFWxZwb_yoW5ZF18p3 48XrWjkFW8Jr1Yyrn8Ar1UG3W5J3WxZa48GrW7Wr1rWF1rG3W7XFy8KFWjkryDtr4UZrya yF90q34xtr1jgaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUka14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc2xSY4AK67AK6FWl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r 4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY 6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x0JUw189UUUUU= X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAwIDAWRrhN4CuQBPsi 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" The previous commit ebad8e731c1c ("media: usb: siano: Fix use after free bugs caused by do_submit_urb") adds cancel_work_sync() in smsusb_stop_streaming(). But smsusb_stop_streaming() may be called, even if the work_struct surb->wq has not been initialized. As a result, the warning will occur. One of the processes that could lead to warning is shown below: smsusb_probe() smsusb_init_device() if (!dev->in_ep || !dev->out_ep || align < 0) { smsusb_term_device(intf); smsusb_stop_streaming() cancel_work_sync(&dev->surbs[i].wq); __cancel_work_timer() __flush_work() if (WARN_ON(!work->func)) // work->func is null The log reported by syzbot is shown below: WARNING: CPU: 0 PID: 897 at kernel/workqueue.c:3066 __flush_work+0x798/0xa8= 0 kernel/workqueue.c:3063 Modules linked in: CPU: 0 PID: 897 Comm: kworker/0:2 Not tainted 6.2.0-rc1-syzkaller #0 RIP: 0010:__flush_work+0x798/0xa80 kernel/workqueue.c:3066 ... RSP: 0018:ffffc9000464ebf8 EFLAGS: 00010246 RAX: 1ffff11002dbb420 RBX: 0000000000000021 RCX: 1ffffffff204fa4e RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff888016dda0e8 RBP: ffffc9000464ed98 R08: 0000000000000001 R09: ffffffff90253b2f R10: 0000000000000001 R11: 0000000000000000 R12: ffff888016dda0e8 R13: ffff888016dda0e8 R14: ffff888016dda100 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd4331efe8 CR3: 000000000b48e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __cancel_work_timer+0x315/0x460 kernel/workqueue.c:3160 smsusb_stop_streaming drivers/media/usb/siano/smsusb.c:182 [inline] smsusb_term_device+0xda/0x2d0 drivers/media/usb/siano/smsusb.c:344 smsusb_init_device+0x400/0x9ce drivers/media/usb/siano/smsusb.c:419 smsusb_probe+0xbbd/0xc55 drivers/media/usb/siano/smsusb.c:567 ... This patch adds check before cancel_work_sync(). If surb->wq has not been initialized, the cancel_work_sync() will not be executed. Reported-by: syzbot+27b0b464864741b18b99@syzkaller.appspotmail.com Fixes: ebad8e731c1c ("media: usb: siano: Fix use after free bugs caused by = do_submit_urb") Signed-off-by: Duoming Zhou --- drivers/media/usb/siano/smsusb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/siano/smsusb.c b/drivers/media/usb/siano/sms= usb.c index 6f443c542c6..640737d3b8a 100644 --- a/drivers/media/usb/siano/smsusb.c +++ b/drivers/media/usb/siano/smsusb.c @@ -179,7 +179,8 @@ static void smsusb_stop_streaming(struct smsusb_device_= t *dev) =20 for (i =3D 0; i < MAX_URBS; i++) { usb_kill_urb(&dev->surbs[i].urb); - cancel_work_sync(&dev->surbs[i].wq); + if (dev->surbs[i].wq.func) + cancel_work_sync(&dev->surbs[i].wq); =20 if (dev->surbs[i].cb) { smscore_putbuffer(dev->coredev, dev->surbs[i].cb); --=20 2.17.1