Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933645AbbKMKrR (ORCPT ); Fri, 13 Nov 2015 05:47:17 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:48784 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932699AbbKMKLe (ORCPT ); Fri, 13 Nov 2015 05:11:34 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Chris Mason , Mark Fasheh , Luis Henriques Subject: [PATCH 3.16.y-ckt 31/94] btrfs: fix use after free iterating extrefs Date: Fri, 13 Nov 2015 10:09:25 +0000 Message-Id: <1447409428-12178-32-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1447409428-12178-1-git-send-email-luis.henriques@canonical.com> References: <1447409428-12178-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2328 Lines: 66 3.16.7-ckt20 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Mason commit dc6c5fb3b514221f2e9d21ee626a9d95d3418dff upstream. The code for btrfs inode-resolve has never worked properly for files with enough hard links to trigger extrefs. It was trying to get the leaf out of a path after freeing the path: btrfs_release_path(path); leaf = path->nodes[0]; item_size = btrfs_item_size_nr(leaf, slot); The fix here is to use the extent buffer we cloned just a little higher up to avoid deadlocks caused by using the leaf in the path. Signed-off-by: Chris Mason cc: Mark Fasheh Reviewed-by: Filipe Manana Reviewed-by: Mark Fasheh Signed-off-by: Luis Henriques --- fs/btrfs/backref.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 54a201dac7f9..b16815417125 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1693,7 +1693,6 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, int found = 0; struct extent_buffer *eb; struct btrfs_inode_extref *extref; - struct extent_buffer *leaf; u32 item_size; u32 cur_offset; unsigned long ptr; @@ -1721,9 +1720,8 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); btrfs_release_path(path); - leaf = path->nodes[0]; - item_size = btrfs_item_size_nr(leaf, slot); - ptr = btrfs_item_ptr_offset(leaf, slot); + item_size = btrfs_item_size_nr(eb, slot); + ptr = btrfs_item_ptr_offset(eb, slot); cur_offset = 0; while (cur_offset < item_size) { @@ -1737,7 +1735,7 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, if (ret) break; - cur_offset += btrfs_inode_extref_name_len(leaf, extref); + cur_offset += btrfs_inode_extref_name_len(eb, extref); cur_offset += sizeof(*extref); } btrfs_tree_read_unlock_blocking(eb); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/