A possible circular locking dependency in ocfs2_del_inode_from_orphan() is detected by syzbot, which occurs due to change in the sequence of acquiring locks. The existing chain is:
&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE] --> &dquot->dq_lock --> &ocfs2_quota_ip_alloc_sem_key
In ocfs2_dio_end_io_write(), &ocfs2_quota_ip_alloc_sem_key is acquired, and then ocfs2_del_inode_from_orphan() is called, which acquires &ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]. This opposes the existing dependency chain:
-> #3 (&ocfs2_quota_ip_alloc_sem_key){++++}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x3a/0x50 kernel/locking/rwsem.c:1590 ocfs2_create_local_dquot+0x19d/0x1a40 fs/ocfs2/quota_local.c:1227 ocfs2_acquire_dquot+0x80f/0xb30 fs/ocfs2/quota_global.c:883 dqget+0x7c1/0xf20 fs/quota/dquot.c:980 __dquot_initialize+0x3b3/0xcb0 fs/quota/dquot.c:1508 ocfs2_get_init_inode+0x13b/0x1b0 fs/ocfs2/namei.c:205 ocfs2_mknod+0x863/0x2050 fs/ocfs2/namei.c:313 ocfs2_create+0x1a5/0x440 fs/ocfs2/namei.c:676 lookup_open fs/namei.c:3796 [inline] open_last_lookups fs/namei.c:3895 [inline] path_openat+0x1500/0x3840 fs/namei.c:4131 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&dquot->dq_lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:547 wait_on_dquot fs/quota/dquot.c:357 [inline] dqget+0x73a/0xf20 fs/quota/dquot.c:975 __dquot_initialize+0x3b3/0xcb0 fs/quota/dquot.c:1508 ocfs2_get_init_inode+0x13b/0x1b0 fs/ocfs2/namei.c:205 ocfs2_mknod+0x863/0x2050 fs/ocfs2/namei.c:313 ocfs2_create+0x1a5/0x440 fs/ocfs2/namei.c:676 lookup_open fs/namei.c:3796 [inline] open_last_lookups fs/namei.c:3895 [inline] path_openat+0x1500/0x3840 fs/namei.c:4131 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x3a/0x50 kernel/locking/rwsem.c:1590 inode_lock include/linux/fs.h:980 [inline] ocfs2_remove_inode fs/ocfs2/inode.c:731 [inline] ocfs2_wipe_inode fs/ocfs2/inode.c:894 [inline] ocfs2_delete_inode fs/ocfs2/inode.c:1155 [inline] ocfs2_evict_inode+0x153d/0x40d0 fs/ocfs2/inode.c:1295 evict+0x504/0x9c0 fs/inode.c:810 do_unlinkat+0x39f/0x570 fs/namei.c:4744 __do_sys_unlinkat fs/namei.c:4778 [inline] __se_sys_unlinkat fs/namei.c:4771 [inline] __x64_sys_unlinkat+0xd3/0xf0 fs/namei.c:4771 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x3a/0x50 kernel/locking/rwsem.c:1590 inode_lock include/linux/fs.h:980 [inline] ocfs2_del_inode_from_orphan+0x134/0x740 fs/ocfs2/namei.c:2730 ocfs2_dio_end_io_write fs/ocfs2/aops.c:2306 [inline] ocfs2_dio_end_io+0x47b/0x1100 fs/ocfs2/aops.c:2404 dio_complete+0x25e/0x790 fs/direct-io.c:281 __blockdev_direct_IO+0x2bc0/0x31f0 fs/direct-io.c:1303 ocfs2_direct_IO+0x260/0x2d0 fs/ocfs2/aops.c:2441 generic_file_direct_write+0x1dc/0x3e0 mm/filemap.c:4189 __generic_file_write_iter+0x120/0x240 mm/filemap.c:4358 ocfs2_file_write_iter+0x157d/0x1d20 fs/ocfs2/file.c:2469 iter_file_splice_write+0x97a/0x10f0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x104/0x160 fs/splice.c:1161 splice_direct_to_actor+0x5b3/0xcd0 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x187/0x270 fs/splice.c:1230 do_sendfile+0x4ec/0x7f0 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fix this by acquiring &ocfs2_quota_ip_alloc_sem_key after acquiring &ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE], effectively calling down_write(&oi->ip_alloc_sem) after the call to ocfs2_del_inode_from_orphan().
Reported-by: syzbot+78359d5fbb04318c35e9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=78359d5fbb04318c35e9 Tested-by: syzbot+78359d5fbb04318c35e9@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Prithvi Tambewagh activprithvi@gmail.com --- fs/ocfs2/aops.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 76c86f1c2b1c..586e3b74d782 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -2295,8 +2295,6 @@ static int ocfs2_dio_end_io_write(struct inode *inode, goto out; }
- down_write(&oi->ip_alloc_sem); - /* Delete orphan before acquire i_rwsem. */ if (dwc->dw_orphaned) { BUG_ON(dwc->dw_writer_pid != task_pid_nr(current)); @@ -2309,6 +2307,8 @@ static int ocfs2_dio_end_io_write(struct inode *inode, mlog_errno(ret); }
+ down_write(&oi->ip_alloc_sem); + di = (struct ocfs2_dinode *)di_bh->b_data;
ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
base-commit: 765e56e41a5af2d456ddda6cbd617b9d3295ab4e