Executive brief
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix the possible bioc_list memory leak during error
There are two possible ways to leak bioc memory on btrfs_ordered_extent::bioc_list:
- An error occurred for btrfs_insert_one_raid_extent() Then the function btrfs_insert_raid_extent() immediately return without freeing any bioc in the bioc_list.
- An ordered extent hit an IO error In that case the ordered extent will have BTRFS_ORDERED_IOERR set, and skip the call on btrfs_insert_raid_extent() completely.
Fix the problem by:
- Introduce a new helper, btrfs_cleanup_ordered_bioc_list() Which will remove all bioc from the bioc_list, and release the bioc.
- Call the above helper for btrfs_insert_raid_extent() So that the cleanup helper is always called no matter what.
- Call the above helper for btrfs_finish_one_ordered() This is called just before the final release on the ordered extent.
This was reported by Sashiko when reviewing another patch.