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 C5E151CEE8E; Tue, 8 Oct 2024 12:31:24 +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=1728390684; cv=none; b=PW33AANBYlAlXxNfW6VhnQJeiJU+fB2/Hay9oODeUdHhPAHCwSmtVoift6Tzw9thkUj3xg8+pghDpGFj12mQoFaDHLdFKcmd4eG1UOFNmt94QOYXg/PY8AdaGQDOakegoFUWsuhDa4VcJMDva9msQcnKJoTMJwDmtrDrkvBtOgQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728390684; c=relaxed/simple; bh=+lTlgmzgtPxxeRh0I7AWeszcSoDsjD8MWAu4WO7S2SE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IugZ7iR0f8eDoZ1hi6j4yDb2PrknRW9YxNagdZ3kGtEif3EvWR6O9fBV6AdIZv5b4GCtems5GQ/3gPEb8MxYdVAXjbd2LJpMHYyk29xBzPqvPjUNPhRmN+LSZ2VVa2bHoULTWBqypI6Fjft0HvP632xGicKPIhHDnv+LL7NfAY8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EELQk8CF; 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="EELQk8CF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3ABF5C4CEC7; Tue, 8 Oct 2024 12:31:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728390684; bh=+lTlgmzgtPxxeRh0I7AWeszcSoDsjD8MWAu4WO7S2SE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EELQk8CFI+PRugfr7zxoKIy7grVRAnO0xOWLbNIVqEfjaYhKYNCbi1KUbXhv6kir3 p1euTxL7EZJCOyEuHQw7OOL+n9ibhZ1K7gxnI7cAsjiePijO/28gSfVayW9+ZaW+Mm Fy8dsxOMiF4/mTEBCKZuPBHyomPzlNh3r7UOTS5k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Baokun Li , Jan Kara , Ojaswin Mujoo , Theodore Tso Subject: [PATCH 6.10 331/482] ext4: fix double brelse() the buffer of the extents path Date: Tue, 8 Oct 2024 14:06:34 +0200 Message-ID: <20241008115701.452781127@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241008115648.280954295@linuxfoundation.org> References: <20241008115648.280954295@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li commit dcaa6c31134c0f515600111c38ed7750003e1b9c upstream. In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================ Fixes: ecb94f5fdf4b ("ext4: collapse a single extent tree block into the inode if possible") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Tested-by: Ojaswin Mujoo Link: https://patch.msgid.link/20240822023545.1994557-9-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1877,6 +1877,7 @@ static void ext4_ext_try_to_merge_up(han path[0].p_hdr->eh_max = cpu_to_le16(max_root); brelse(path[1].p_bh); + path[1].p_bh = NULL; ext4_free_blocks(handle, inode, NULL, blk, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); }