Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write

A circular locking dependency involves INODE_ALLOC_SYSTEM_INODE, EXTENT_ALLOC_SYSTEM_INODE, and ORPHAN_DIR_SYSTEM_INODE.

1. ocfs2_mknod() acquires INODE_ALLOC then EXTENT_ALLOC.

2. ocfs2_dio_end_io_write() acquires EXTENT_ALLOC for unwritten extents, then ORPHAN_DIR via ocfs2_del_inode_from_orphan() while still holding EXTENT_ALLOC.

3. ocfs2_wipe_inode() acquires ORPHAN_DIR then INODE_ALLOC via ocfs2_remove_inode.

Break the cycle in ocfs2_dio_end_io_write() by freeing the allocation contexts (releasing EXTENT_ALLOC) before acquiring ORPHAN_DIR.

WARNING: possible circular locking dependency detected ------------------------------------------------------ is trying to acquire lock: ffff8881e78b33a0 (&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_evict_inode+0x1539/0x43b0 fs/ocfs2/inode.c:1299

but task is already holding lock: ffff8881e78b4fa0 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_evict_inode+0xe97/0x43b0 fs/ocfs2/inode.c:1299

the existing dependency chain (in reverse order) is:

-> #2 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}: inode_lock include/linux/fs.h:1029 [inline] ocfs2_del_inode_from_orphan+0x12e/0x7a0 fs/ocfs2/namei.c:2728 ocfs2_dio_end_io+0xf9c/0x1370 fs/ocfs2/aops.c:2418 dio_complete+0x25b/0x790 fs/direct-io.c…