Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932989AbbKLXtp (ORCPT ); Thu, 12 Nov 2015 18:49:45 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:45294 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932444AbbKLXTY (ORCPT ); Thu, 12 Nov 2015 18:19:24 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Chris Mason , Mark Fasheh , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 079/155] btrfs: fix use after free iterating extrefs Date: Thu, 12 Nov 2015 15:17:13 -0800 Message-Id: <1447370309-357-80-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1447370309-357-1-git-send-email-kamal@canonical.com> References: <1447370309-357-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2319 Lines: 69 3.19.8-ckt10 -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: Kamal Mostafa --- 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 8729cf6..6a659c2 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1785,7 +1785,6 @@ 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; @@ -1813,9 +1812,8 @@ 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) { @@ -1829,7 +1827,7 @@ 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); -- 1.9.1 -- 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/