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 0F0B827F00A for ; Mon, 20 Oct 2025 16:16:09 +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=1760976970; cv=none; b=O/WxyFOeskFnagCMKzrJXvlrCYgUvonJSV8kmuP33A7HEFo/QRtOorY+VTxIgX0QcHb8jls8Ve5N9Lupb4sKfpR6L8TDRKGdG6NuXx5oROvQDZOx9i9Xb9f0gYmDAB+c08Gh+LcKuhsSjz0Ll7Whs1NMZEIY6gHxPqq6IdMXaKo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760976970; c=relaxed/simple; bh=h4fIqP79GSp7vEar+qmejlnqSrD6GaDEAk+HT0Hmp70=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m6waX39O7yPigxpHusiJYJEVvYAcicjurDKFWwYj+7Fl3fp+fBOZLDybXbbIZaZh7J7NTHqvO52XZD6hit9GahR5fuZocKMLv1CXeCCBRymMqeNyPUwLXYvWSpiusxnRss9tt7QIzH6OE4SFULXmTl0aBhVb3gbyNyuB7Ymkvmo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XdY8yuGX; 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="XdY8yuGX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11358C4CEFE; Mon, 20 Oct 2025 16:16:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760976969; bh=h4fIqP79GSp7vEar+qmejlnqSrD6GaDEAk+HT0Hmp70=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XdY8yuGXiF1Gccks0LAq3pidP0fE+3y4jpL09pLNeq3qBGD1bCta43UhKmT8ZCnCH iwL/o09pgFgiPqxdL6Nbrt07eRKv97PqPG27U0EzeQPcHA2HL7w575lVAczYk9RKnG tueUHdyjMd3tyzdusJiqqEL7i0OHJYkZpr6mVKiNgcqASToCmvPSneYw8s4N432aQY pg/5xeXv3DD0gyLVzwxlID62oL90sBzbMQydoJ5dSmNVd3mfmxkyE1cIf18kd8dNWs 4idI8xcwKGgNsfwPV2RGz9RLLBOUm5nWIBbq2rlvaUStcRUBIn7VeRDAzQFr3iaiAO nDD1mFyV3Me2A== From: Sasha Levin To: stable@vger.kernel.org Cc: Shashank A P , Jan Kara , Sasha Levin Subject: [PATCH 6.6.y 2/2] fs: quota: create dedicated workqueue for quota_release_work Date: Mon, 20 Oct 2025 12:16:05 -0400 Message-ID: <20251020161605.1834667-2-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251020161605.1834667-1-sashal@kernel.org> References: <2025101650-tighten-fleshed-6fe0@gregkh> <20251020161605.1834667-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- 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 ba227502b03d7..42a7d0a71b22e 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -163,6 +163,9 @@ static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES; /* 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); -- 2.51.0