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 1BE52274B44; Tue, 21 Oct 2025 19:57:00 +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=1761076620; cv=none; b=hs+qtxZjpWC81lk/5K8JJ1pFLlsFV6sVG3uWg02F0k0MI/BJRaUoYIHO2knHOEm6g/ulPCNg5ZtEN+xgGevzpwLKdCK3I+iaM3AbIu1V8VTvtHt0Mv9sNwMbtcslXLSX8bVBLd9RWKYu4DZEcvCxETA1YqZYA9VaMw3RhHAKnMA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761076620; c=relaxed/simple; bh=J+1+dF1tVLBbd/2NGWukJ0ppl2bDYHx1uo0xGmAZZdY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uRCCtd0Ns59eHU2MaYKTNQy4KOjIuT41n8H2NCJQcUALllC7K8571cOaE0uLNHdhfVsPn/xN/BQVnyktSoEq4y6TChLhLav5GxZPP9VwRiW4nE/+rDYw4MkB4XdZL+z3vHxce52nHpBE9PSPbdJjQpbdKQfXyUwWf+tRcSjFUVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=V/YhfQbV; 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="V/YhfQbV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79B59C4CEF1; Tue, 21 Oct 2025 19:56:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1761076619; bh=J+1+dF1tVLBbd/2NGWukJ0ppl2bDYHx1uo0xGmAZZdY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V/YhfQbVlrnXvYuHRwCJ1HsNrE2YM4gmtRBpgi7rT2JCEq1ktjJNkzemVMCkJlGx+ tpRNdgokROFqnwIBzYzbGUetR7XM77pOthh0p9mCe8gpnyBKTqflxtw/pK0l5Wtb+s DmPMTdYIPpCETLETvyCau6JeDbH16CBF5a6FOtUY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shashank A P , Jan Kara , Sasha Levin Subject: [PATCH 6.6 090/105] fs: quota: create dedicated workqueue for quota_release_work Date: Tue, 21 Oct 2025 21:51:39 +0200 Message-ID: <20251021195023.787915016@linuxfoundation.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251021195021.492915002@linuxfoundation.org> References: <20251021195021.492915002@linuxfoundation.org> User-Agent: quilt/0.69 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shashank A P [ Upstream commit 72b7ceca857f38a8ca7c5629feffc63769638974 ] 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_dependency+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 Link: https://patch.msgid.link/20250901092905.2115-1-shashank.ap@samsung.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/quota/dquot.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -163,6 +163,9 @@ static struct quota_module_name module_n /* SLAB cache for dquot structures */ static struct kmem_cache *dquot_cachep; +/* workqueue for work quota_release_work*/ +static struct workqueue_struct *quota_unbound_wq; + void register_quota_format(struct quota_format_type *fmt) { spin_lock(&dq_list_lock); @@ -891,7 +894,7 @@ 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); @@ -3046,6 +3049,11 @@ static int __init dquot_init(void) if (register_shrinker(&dqcache_shrinker, "dquota-cache")) panic("Cannot register dquot shrinker"); + quota_unbound_wq = 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);