This is a note to let you know that I've just added the patch titled
btrfs: fix use after free iterating extrefs
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-fix-use-after-free-iterating-extrefs.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From dc6c5fb3b514221f2e9d21ee626a9d95d3418dff Mon Sep 17 00:00:00 2001
From: Chris Mason <[email protected]>
Date: Tue, 13 Oct 2015 14:06:48 -0400
Subject: btrfs: fix use after free iterating extrefs
From: Chris Mason <[email protected]>
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 <[email protected]>
cc: Mark Fasheh <[email protected]>
Reviewed-by: Filipe Manana <[email protected]>
Reviewed-by: Mark Fasheh <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/btrfs/backref.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1809,7 +1809,6 @@ 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;
@@ -1837,9 +1836,8 @@ 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) {
@@ -1853,7 +1851,7 @@ 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);
Patches currently in stable-queue which might be from [email protected] are
queue-4.2/btrfs-check-unsupported-filters-in-balance-arguments.patch
queue-4.2/btrfs-fix-use-after-free-iterating-extrefs.patch
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