From nobody Fri Oct 3 12:14:28 2025 Received: from mailout3.samsung.com (mailout3.samsung.com [203.254.224.33]) (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 8B8D430DD29 for ; Mon, 1 Sep 2025 09:29:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.33 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756718997; cv=none; b=SCQQxJh/3f6twFg9nAyvJ/3y2vXFxxCMIdLeQZ3BP8czHcEChs7AbtS0BWerIaZLdigB6IvH3tIRVvR8OyWCb9io2ntJViBehHCOq9DFCPbq9hElJkAroSZUUq7NCOm8g326qQO1spV5JzOh1X0GbytqrIA0+zebGUBBwBGgIlQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756718997; c=relaxed/simple; bh=qZJxbmaqGWsy4atFe2P3rGVqkuLG6BlTXh6WeAcAyhU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type: References; b=n3dDnc34l+nTCX8AOQznmkcZDdycOTwVrvPxEuH7kcI6Jq2vdI4kqCMHECTuQughtaxcAUo2Wv4UenRcSWqQE/PoMDkiIutA+YJmWITtJBoEkXWgWwWpRlhS4339x885JgCZKBodLgEznBBpdKswsac2P5BKaAIXrZCA4SnYYfQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=duhoG9Vf; arc=none smtp.client-ip=203.254.224.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="duhoG9Vf" Received: from epcas5p3.samsung.com (unknown [182.195.41.41]) by mailout3.samsung.com (KnoxPortal) with ESMTP id 20250901092952epoutp038b53c8205386eaf52abb52edf9559bed~hHp3LfCmo1906019060epoutp03l for ; Mon, 1 Sep 2025 09:29:52 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout3.samsung.com 20250901092952epoutp038b53c8205386eaf52abb52edf9559bed~hHp3LfCmo1906019060epoutp03l DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1756718992; bh=74Q1v6jsTAK/snjr8Bol8mkXpMT6PrDDB7mwBUaLBDo=; h=From:To:Cc:Subject:Date:References:From; b=duhoG9Vfo9MZOdJwEUweOVti6TF5ssKEaXuBHMXGEot2BY0fWmc9P0IBHlRSrsThv tOpfjQieTm9YhADMDRenITqN/7yWck6ARrjqndgd8fQjNwztCOUxyzUKyQJx9D9emj vhEPYe+CdkbzK61hgNNRDZTZLN/WrKt0Lsvg300o= Received: from epsnrtp02.localdomain (unknown [182.195.42.154]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPS id 20250901092952epcas5p15f9c1d6b59500aeac07e20af90cad9f6~hHp20veHp1370913709epcas5p13; Mon, 1 Sep 2025 09:29:52 +0000 (GMT) Received: from epcas5p3.samsung.com (unknown [182.195.38.86]) by epsnrtp02.localdomain (Postfix) with ESMTP id 4cFk9W4mCWz2SSKY; Mon, 1 Sep 2025 09:29:51 +0000 (GMT) Received: from epsmtip2.samsung.com (unknown [182.195.34.31]) by epcas5p3.samsung.com (KnoxPortal) with ESMTPA id 20250901092950epcas5p35accdcb60fe3ba58772289058a12f8a1~hHp1a6Xqt2257322573epcas5p34; Mon, 1 Sep 2025 09:29:50 +0000 (GMT) Received: from INBRO002811.samsungds.net (unknown [107.122.5.126]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20250901092949epsmtip23b4ed2198fb6b60b6d40969701766613~hHpz3yNss1644216442epsmtip2H; Mon, 1 Sep 2025 09:29:49 +0000 (GMT) From: Shashank A P To: jack@suse.com, linux-kernel@vger.kernel.org Cc: shadakshar.i@samsung.com, thiagu.r@samsung.com, hy50.seo@samsung.com, kwangwon.min@samsung.com, alim.akhtar@samsung.com, h10.kim@samsung.com, kwmad.kim@samsung.com, selvarasu.g@samsung.com, Shashank A P , stable@vger.kernel.org Subject: [PATCH] fs: quota: create dedicated workqueue for quota_release_work Date: Mon, 1 Sep 2025 14:59:00 +0530 Message-ID: <20250901092905.2115-1-shashank.ap@samsung.com> X-Mailer: git-send-email 2.46.0.windows.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CMS-MailID: 20250901092950epcas5p35accdcb60fe3ba58772289058a12f8a1 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" CMS-TYPE: 105P cpgsPolicy: CPGSC10-542,Y X-CFilter-Loop: Reflected X-CMS-RootMailID: 20250901092950epcas5p35accdcb60fe3ba58772289058a12f8a1 References: There is a kernel panic due to WARN_ONCE when panic_on_warn is set. This issue occurs when writeback is triggered due to sync call for an opened file(ie, writeback reason is WB_REASON_SYNC). When f2fs balance is needed at sync path, flush for quota_release_work is triggered. By default quota_release_work is queued to "events_unbound" queue which does not have WQ_MEM_RECLAIM flag. During f2fs balance "writeback" workqueue tries to flush quota_release_work causing kernel panic due to MEM_RECLAIM flag mismatch errors. This patch creates dedicated workqueue with WQ_MEM_RECLAIM flag for work quota_release_work. ------------[ cut here ]------------ WARNING: CPU: 4 PID: 14867 at kernel/workqueue.c:3721 check_flush_dependenc= y+0x13c/0x148 Call trace: check_flush_dependency+0x13c/0x148 __flush_work+0xd0/0x398 flush_delayed_work+0x44/0x5c dquot_writeback_dquots+0x54/0x318 f2fs_do_quota_sync+0xb8/0x1a8 f2fs_write_checkpoint+0x3cc/0x99c f2fs_gc+0x190/0x750 f2fs_balance_fs+0x110/0x168 f2fs_write_single_data_page+0x474/0x7dc f2fs_write_data_pages+0x7d0/0xd0c do_writepages+0xe0/0x2f4 __writeback_single_inode+0x44/0x4ac writeback_sb_inodes+0x30c/0x538 wb_writeback+0xf4/0x440 wb_workfn+0x128/0x5d4 process_scheduled_works+0x1c4/0x45c worker_thread+0x32c/0x3e8 kthread+0x11c/0x1b0 ret_from_fork+0x10/0x20 Kernel panic - not syncing: kernel: panic_on_warn set ... Fixes: ac6f420291b3 ("quota: flush quota_release_work upon quota writeback") CC: stable@vger.kernel.org Signed-off-by: Shashank A P --- fs/quota/dquot.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index df4a9b348769..d0f83a0c42df 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -162,6 +162,9 @@ static struct quota_module_name module_names[] =3D INIT= _QUOTA_MODULE_NAMES; /* SLAB cache for dquot structures */ static struct kmem_cache *dquot_cachep; =20 +/* workqueue for work quota_release_work*/ +struct workqueue_struct *quota_unbound_wq; + void register_quota_format(struct quota_format_type *fmt) { spin_lock(&dq_list_lock); @@ -881,7 +884,7 @@ void dqput(struct dquot *dquot) put_releasing_dquots(dquot); atomic_dec(&dquot->dq_count); spin_unlock(&dq_list_lock); - queue_delayed_work(system_unbound_wq, "a_release_work, 1); + queue_delayed_work(quota_unbound_wq, "a_release_work, 1); } EXPORT_SYMBOL(dqput); =20 @@ -3041,6 +3044,11 @@ static int __init dquot_init(void) =20 shrinker_register(dqcache_shrinker); =20 + quota_unbound_wq =3D alloc_workqueue("quota_events_unbound", + WQ_UNBOUND | WQ_MEM_RECLAIM, WQ_MAX_ACTIVE); + if (!quota_unbound_wq) + panic("Cannot create quota_unbound_wq\n"); + return 0; } fs_initcall(dquot_init); --=20 2.34.1