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 4A4AB17555 for ; Fri, 14 Feb 2025 17:16:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739553413; cv=none; b=CF3fOlDPZE9+fVCUSct01NccsnlVrhS0TQ+0BJCEPOZ6IJEJtcG8LGs/56dyD42Ismr2osUh2n2dEUsEEZIN5pzA5vWdmPnX+iZx3uITMpk10Obdk0vWcOBWJnb+PvlZGgsHviOezBVCMPyOcraTcgjPBMqeGC3VuUP0GxoTLLY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739553413; c=relaxed/simple; bh=+Dh7vng6Bg6Mj4vQ2+6Vhnpc0aT2Z3+xpd0XciJ3YDU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=couo9eKyxQMifs8EtW5GbiaKkRXEb097Nu4LAYhFmjOL86LDJd4fgA25WjYfktY4YldT+5rSBTzMeDPHAC1nj9pOpBjieSowkx4Y8HmdHHvmcfvxCppNDXy2nCX8kiuMVpvUc5zg2XUebuxIjpk0aRDMTwc3u6YRvV1sQCbF9G0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WbqKOlEY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WbqKOlEY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1588C4CED1; Fri, 14 Feb 2025 17:16:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739553412; bh=+Dh7vng6Bg6Mj4vQ2+6Vhnpc0aT2Z3+xpd0XciJ3YDU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WbqKOlEYHEmP5UIvcFQzH7iB6GHQ+zDoDhGYB/DOIMEOF/swjY+sEYPGeuOphrnny tKhRuqm8sSplP6I+FRgbFbKwyj44M7OWWrn5PE9HjpZDXDksyZjXlYeXMcYZBSqkJ9 R2AYvm50qNF7DiLra4vbYiIFlXF4oSrj0vyhx3alAhELPKiXYQPTOJ0fC6A5LlXvnV koTuIOyHjNnTSSDLNN3fs4CcJFoTlT63vlUmMgh34cvCHl0JVw8oYILwxVnBdsKXjA 0ScLyR359zQG9n45eZfcg5jEaDRNGCqOquwuXEJzNTYGifnpeRmQCn6IoXV9aEyXpf sqw1i6r1N+WFA== Date: Fri, 14 Feb 2025 07:16:51 -1000 From: Tejun Heo To: Will Deacon Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Marc Zyngier , Lai Jiangshan Subject: Re: [PATCH] workqueue: Log additional details when rejecting work Message-ID: References: <20250214164349.13694-1-will@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250214164349.13694-1-will@kernel.org> On Fri, Feb 14, 2025 at 04:43:49PM +0000, Will Deacon wrote: > Syzbot regularly runs into the following warning on arm64: > > | WARNING: CPU: 1 PID: 6023 at kernel/workqueue.c:2257 current_wq_worker kernel/workqueue_internal.h:69 [inline] > | WARNING: CPU: 1 PID: 6023 at kernel/workqueue.c:2257 is_chained_work kernel/workqueue.c:2199 [inline] > | WARNING: CPU: 1 PID: 6023 at kernel/workqueue.c:2257 __queue_work+0xe50/0x1308 kernel/workqueue.c:2256 > | Modules linked in: > | CPU: 1 UID: 0 PID: 6023 Comm: klogd Not tainted 6.13.0-rc2-syzkaller-g2e7aff49b5da #0 > | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 > | pstate: 404000c5 (nZcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > | pc : __queue_work+0xe50/0x1308 kernel/workqueue_internal.h:69 > | lr : current_wq_worker kernel/workqueue_internal.h:69 [inline] > | lr : is_chained_work kernel/workqueue.c:2199 [inline] > | lr : __queue_work+0xe50/0x1308 kernel/workqueue.c:2256 > > [...] > > | __queue_work+0xe50/0x1308 kernel/workqueue.c:2256 (L) > | delayed_work_timer_fn+0x74/0x90 kernel/workqueue.c:2485 > | call_timer_fn+0x1b4/0x8b8 kernel/time/timer.c:1793 > | expire_timers kernel/time/timer.c:1839 [inline] > | __run_timers kernel/time/timer.c:2418 [inline] > | __run_timer_base+0x59c/0x7b4 kernel/time/timer.c:2430 > | run_timer_base kernel/time/timer.c:2439 [inline] > | run_timer_softirq+0xcc/0x194 kernel/time/timer.c:2449 > > The warning is probably because we are trying to queue work into a > destroyed workqueue, but the softirq context makes it hard to pinpoint > the problematic caller. > > Extend the warning diagnostics to print both the function we are trying > to queue as well as the name of the workqueue. > > Cc: Tejun Heo > Cc: Catalin Marinas > Cc: Marc Zyngier > Cc: Lai Jiangshan > Link: https://syzkaller.appspot.com/bug?extid=e13e654d315d4da1277c > Signed-off-by: Will Deacon Applied to wq/for-6.14-fixes. Thanks. -- tejun