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 8A0CE223C55; Thu, 12 Dec 2024 17:45:38 +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=1734025538; cv=none; b=OXRLsNKpOOjowNM5ld35pwTpZyIt7ktwKAazeErWgnZutbsRo/FC39eBIXULiqr8R/hYbuwTAE0uWMP3DxmaU6/VLhLCBWuc/uNfmF4r0D+c52sEZGj1apmsuQA1dJ4Rx5hGWvEpAKz0GP5LN6+SETAtOlsECCyK3Pg3ElD2qs4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734025538; c=relaxed/simple; bh=n8C0TOess7nUBYbBQxU7/r98/O5okIe6HWsfVjRAdJw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qhz7y57P1zeLK9rcJ8FZBVyQXoE2ky3W2dwZYHdmTIB0TiEXF8/HqRIVHLACUIRQoKfDYXpWgoVB2DprCb/60J5b2SwjLug7iAY13jOPE8yj1Jo2yJoc2jCqTS4BvDbIw/eiflvbb0GO8hrt63zCsrdcYlAEpMfMh00l3tEnnpU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hh4GpyeL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hh4GpyeL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8536C4CECE; Thu, 12 Dec 2024 17:45:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734025538; bh=n8C0TOess7nUBYbBQxU7/r98/O5okIe6HWsfVjRAdJw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hh4GpyeLLQjYXzGAtytB5JaPln9f3T/midJuvL9SbZ2D+cgVma/PY0DwXJ0HVv6nN oRe/3em/mcfUimQbalmPQ+dzk4Mmm+Y+LDcrhkzZOSFEmys7y+g/EUN+X/xJnc+haC e27S7M6pAJ2AyOFbxlelbeZVYlzfqYJhxV3STDBs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Disha Goel , Baokun Li , Ojaswin Mujoo , Jan Kara , Sasha Levin Subject: [PATCH 5.4 202/321] quota: flush quota_release_work upon quota writeback Date: Thu, 12 Dec 2024 16:02:00 +0100 Message-ID: <20241212144237.959751462@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144229.291682835@linuxfoundation.org> References: <20241212144229.291682835@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ojaswin Mujoo [ Upstream commit ac6f420291b3fee1113f21d612fa88b628afab5b ] One of the paths quota writeback is called from is: freeze_super() sync_filesystem() ext4_sync_fs() dquot_writeback_dquots() Since we currently don't always flush the quota_release_work queue in this path, we can end up with the following race: 1. dquot are added to releasing_dquots list during regular operations. 2. FS Freeze starts, however, this does not flush the quota_release_work queue. 3. Freeze completes. 4. Kernel eventually tries to flush the workqueue while FS is frozen which hits a WARN_ON since transaction gets started during frozen state: ext4_journal_check_start+0x28/0x110 [ext4] (unreliable) __ext4_journal_start_sb+0x64/0x1c0 [ext4] ext4_release_dquot+0x90/0x1d0 [ext4] quota_release_workfn+0x43c/0x4d0 Which is the following line: WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE); Which ultimately results in generic/390 failing due to dmesg noise. This was detected on powerpc machine 15 cores. To avoid this, make sure to flush the workqueue during dquot_writeback_dquots() so we dont have any pending workitems after freeze. Reported-by: Disha Goel CC: stable@vger.kernel.org Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Reviewed-by: Baokun Li Signed-off-by: Ojaswin Mujoo Signed-off-by: Jan Kara Link: https://patch.msgid.link/20241121123855.645335-2-ojaswin@linux.ibm.com Signed-off-by: Sasha Levin --- fs/quota/dquot.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 14c0dd5b65a43..42c2ac0cc8fc9 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -681,6 +681,8 @@ int dquot_writeback_dquots(struct super_block *sb, int type) WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount)); + flush_delayed_work("a_release_work); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (type != -1 && cnt != type) continue; -- 2.43.0