From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5DC80318B96; Thu, 28 May 2026 20:51:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780001505; cv=none; b=doS/MD0lTn9D/BIfUclDEW8A6K33KcVXUc6Ex92WEoJ//mZyADMJu9a3BymbcSQCD6hpYUBRwDamHe/+roe/RQETq3UrZNCbKmuT7OHcIsYtb1J/33FCDsB5gJNxo6qnAcY7b8utgzXDWySy5/N0jspMtwJlstXIkoHX/7ZUroA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780001505; c=relaxed/simple; bh=zoV6Kxr7T3sU/8gSBICSfw25Z5MAn9loIQ8ydH+D+Ik=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BE7OEiufkPTQ8dMZVhpsZEuMquL+yIuOKXHU4jVSxAfX6epVvuUQnnjcT//DLEOLuphtHkLMAp6rtkbcAo8Bb9A//FVe3Oq/qmN8P9LfYc3wi1mkqnc0oDwi5SigjI2emzicl04fWWlrYminTKvplUmclLpZ+c9GtXXcnpYCCXg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jY94ReaZ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jY94ReaZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AE9F1F000E9; Thu, 28 May 2026 20:51:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780001504; bh=Lzyn6t1kLePDu9FWevcGccVKt8/p7PJCxnrtTsSZcSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jY94ReaZnT5VzgVWm4jtx9dZf40j/xBvCc/NKz4OLVMPX0/P+11fAkcf/Awx/ei3d roqcL1SR7EcewHueWh3sRSYP8ZBGOVfUJNvoxDdQTYVp/5c5jVGC5/uTKRkNGjY74a Z8IS973KrlFwbgKKtWFU4afbvRZEa/FKJLcJ0prw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Boris Burkov , Filipe Manana , David Sterba , Sasha Levin Subject: [PATCH 6.6 105/186] btrfs: tracepoints: fix sleep while in atomic context in btrfs_sync_file() Date: Thu, 28 May 2026 21:49:45 +0200 Message-ID: <20260528194931.771308885@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194928.941004471@linuxfoundation.org> References: <20260528194928.941004471@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: Filipe Manana [ Upstream commit c73370c677646e86fc4b1780fb07027bdf847375 ] The trace event btrfs_sync_file() is called in an atomic context (all trace events are) and its call to dput(), which is needed due to the call to dget_parent(), can sleep, triggering a kernel splat. This can be reproduced by enabling the trace event and running btrfs/056 from fstests for example. The splat shown in dmesg is the following: [53.919] BUG: sleeping function called from invalid context at fs/dcache.c:970 [53.947] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 32773, name: xfs_io [53.988] preempt_count: 2, expected: 0 [53.967] RCU nest depth: 0, expected: 0 [53.943] Preemption disabled at: [53.944] [<0000000000000000>] 0x0 [54.078] CPU: 0 UID: 0 PID: 32773 Comm: xfs_io Tainted: G W 7.1.0-rc1-btrfs-next-232+ #1 PREEMPT(full) [54.070] Tainted: [W]=WARN [54.071] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [54.072] Call Trace: [54.074] [54.076] dump_stack_lvl+0x56/0x80 [54.079] __might_resched.cold+0xd6/0x10f [54.072] dput.part.0+0x24/0x110 [54.078] trace_event_raw_event_btrfs_sync_file+0x75/0x140 [btrfs] [54.089] btrfs_sync_file+0x1ed/0x530 [btrfs] [54.087] ? __handle_mm_fault+0x8ae/0xed0 [54.089] btrfs_do_write_iter+0x172/0x210 [btrfs] [54.091] vfs_write+0x21f/0x450 [54.094] __x64_sys_pwrite64+0x8d/0xc0 [54.096] ? do_user_addr_fault+0x20c/0x670 [54.099] do_syscall_64+0x60/0xf20 [54.092] ? clear_bhb_loop+0x60/0xb0 [54.094] entry_SYSCALL_64_after_hwframe+0x76/0x7e So stop using dget_parent() and dput() and access the parent dentry directly as dentry->d_parent. This is also what ext4 is doing in its equivalent trace event ext4_sync_file_enter(). Fixes: a85b46db143f ("btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()") Reviewed-by: Boris Burkov Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- include/trace/events/btrfs.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index 2364c68df76c4..e06dbddc2872f 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -791,10 +791,8 @@ TRACE_EVENT(btrfs_sync_file, TP_fast_assign( struct dentry *dentry = file_dentry(file); struct inode *inode = file_inode(file); - struct dentry *parent = dget_parent(dentry); - struct inode *parent_inode = d_inode(parent); + struct inode *parent_inode = d_inode(dentry->d_parent); - dput(parent); TP_fast_assign_fsid(btrfs_sb(inode->i_sb)); __entry->ino = btrfs_ino(BTRFS_I(inode)); __entry->parent = btrfs_ino(BTRFS_I(parent_inode)); -- 2.53.0