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Date: Fri, 23 Oct 2015 10:45:55 -0700 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Chris Mason <clm@...com>, Mark Fasheh <mfasheh@...e.de>, Filipe Manana <fdmanana@...e.com> Subject: [PATCH 3.14 14/25] btrfs: fix use after free iterating extrefs 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Mason <clm@...com> 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 <clm@...com> cc: Mark Fasheh <mfasheh@...e.de> Reviewed-by: Filipe Manana <fdmanana@...e.com> Reviewed-by: Mark Fasheh <mfasheh@...e.de> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- fs/btrfs/backref.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1692,7 +1692,6 @@ static int iterate_inode_extrefs(u64 inu 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; @@ -1720,9 +1719,8 @@ static int iterate_inode_extrefs(u64 inu 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) { @@ -1736,7 +1734,7 @@ static int iterate_inode_extrefs(u64 inu 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@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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