Btrfs: eliminate a use-after-free in btrfs_balance()
Commit 5af3e8cc introduced a use-after-free at volumes.c:3139: bctl is freed
above in __cancel_balance() in all cases except for balance pause. Fix this
by moving the offending check a couple statements above, the meaning of the
check is preserved.
Reported-by: Chris Mason <chris.mason@fusionio.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 305b6a6..d778e96 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3195,6 +3195,11 @@
mutex_lock(&fs_info->balance_mutex);
atomic_dec(&fs_info->balance_running);
+ if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+ fs_info->num_tolerated_disk_barrier_failures =
+ btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
+ }
+
if (bargs) {
memset(bargs, 0, sizeof(*bargs));
update_ioctl_balance_args(fs_info, 0, bargs);
@@ -3205,11 +3210,6 @@
__cancel_balance(fs_info);
}
- if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
- fs_info->num_tolerated_disk_barrier_failures =
- btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
- }
-
wake_up(&fs_info->balance_wait_q);
return ret;