possible deadlock in ocfs2_start_trans

Status: upstream: reported on 2026/07/23 04:08
Reported-by: syzbot+6c85490eac27b17f0113@syzkaller.appspotmail.com
First crash: 20d, last: 20d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ocfs2_start_trans ocfs2 4 1 616d 612d 0/29 auto-obsoleted due to no activity on 2025/03/15 01:59

Sample crash report:
(syz-executor,4193,0):__ocfs2_flush_truncate_log:6055 ERROR: status = -30
(syz-executor,4193,0):ocfs2_truncate_log_shutdown:6320 ERROR: status = -30
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor/4193 is trying to acquire lock:
ffff8880222b7938 ((wq_completion)ocfs2_wq){+.+.}-{0:0}, at: flush_workqueue+0x14e/0x1390 kernel/workqueue.c:2830

but task is already holding lock:
ffff888060c810e8 (&journal->j_trans_barrier){.+.+}-{3:3}, at: ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&journal->j_trans_barrier){.+.+}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374
       ocfs2_shutdown_local_alloc+0x1f3/0xac0 fs/ocfs2/localalloc.c:416
       ocfs2_dismount_volume+0x1e1/0x890 fs/ocfs2/super.c:1885
       generic_shutdown_super+0x130/0x300 fs/super.c:475
       kill_block_super+0x7c/0xe0 fs/super.c:1427
       deactivate_locked_super+0x93/0xf0 fs/super.c:335
       cleanup_mnt+0x426/0x4d0 fs/namespace.c:1148
       task_work_run+0x125/0x1a0 kernel/task_work.c:188
       tracehook_notify_resume include/linux/tracehook.h:189 [inline]
       exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
       __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #4 (sb_internal#4){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_intwrite include/linux/fs.h:1928 [inline]
       ocfs2_start_trans+0x2a7/0x6f0 fs/ocfs2/journal.c:372
       ocfs2_write_begin_inline fs/ocfs2/aops.c:1484 [inline]
       ocfs2_try_to_write_inline_data fs/ocfs2/aops.c:1587 [inline]
       ocfs2_write_begin_nolock+0x207c/0x44b0 fs/ocfs2/aops.c:1673
       ocfs2_write_begin+0x1b4/0x310 fs/ocfs2/aops.c:1907
       generic_perform_write+0x2b6/0x550 mm/filemap.c:3785
       __generic_file_write_iter+0x261/0x4e0 mm/filemap.c:3912
       ocfs2_file_write_iter+0x171a/0x1ee0 fs/ocfs2/file.c:2472
       call_write_iter include/linux/fs.h:2173 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0x748/0xd70 fs/read_write.c:594
       ksys_write+0x153/0x260 fs/read_write.c:647
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #3 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_read_virt_blocks+0x240/0x8e0 fs/ocfs2/extent_map.c:984
       ocfs2_read_dir_block fs/ocfs2/dir.c:508 [inline]
       ocfs2_find_entry_el fs/ocfs2/dir.c:715 [inline]
       ocfs2_find_entry+0x39d/0x1f90 fs/ocfs2/dir.c:1091
       ocfs2_find_files_on_disk+0xdb/0x2f0 fs/ocfs2/dir.c:1995
       ocfs2_lookup_ino_from_name+0x4f/0xf0 fs/ocfs2/dir.c:2017
       _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
       ocfs2_get_system_file_inode+0x33f/0x7f0 fs/ocfs2/sysfile.c:112
       ocfs2_init_global_system_inodes+0x315/0x6e0 fs/ocfs2/super.c:458
       ocfs2_initialize_super fs/ocfs2/super.c:2279 [inline]
       ocfs2_fill_super+0x4032/0x50c0 fs/ocfs2/super.c:995
       mount_bdev+0x28a/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x247/0xa40 fs/namespace.c:3034
       do_mount fs/namespace.c:3377 [inline]
       __do_sys_mount fs/namespace.c:3585 [inline]
       __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #2 (&osb->system_file_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       ocfs2_get_system_file_inode+0x1a4/0x7f0 fs/ocfs2/sysfile.c:101
       ocfs2_queue_orphans fs/ocfs2/journal.c:2149 [inline]
       ocfs2_recover_orphans fs/ocfs2/journal.c:2249 [inline]
       ocfs2_complete_recovery+0xbb7/0x2110 fs/ocfs2/journal.c:1311
       process_one_work+0x867/0xff0 kernel/workqueue.c:2310
       worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
       kthread+0x42e/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #1 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}:
       process_one_work+0x7ba/0xff0 kernel/workqueue.c:2286
       worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
       kthread+0x42e/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #0 ((wq_completion)ocfs2_wq){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       flush_workqueue+0x16a/0x1390 kernel/workqueue.c:2830
       ocfs2_recovery_disable+0x2ba/0x350 fs/ocfs2/journal.c:227
       ocfs2_recovery_exit+0x16/0x50 fs/ocfs2/journal.c:241
       ocfs2_dismount_volume+0x1f1/0x890 fs/ocfs2/super.c:1890
       generic_shutdown_super+0x130/0x300 fs/super.c:475
       kill_block_super+0x7c/0xe0 fs/super.c:1427
       deactivate_locked_super+0x93/0xf0 fs/super.c:335
       cleanup_mnt+0x426/0x4d0 fs/namespace.c:1148
       task_work_run+0x125/0x1a0 kernel/task_work.c:188
       tracehook_notify_resume include/linux/tracehook.h:189 [inline]
       exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
       __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  (wq_completion)ocfs2_wq --> sb_internal#4 --> &journal->j_trans_barrier

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&journal->j_trans_barrier);
                               lock(sb_internal#4);
                               lock(&journal->j_trans_barrier);
  lock((wq_completion)ocfs2_wq);

 *** DEADLOCK ***

4 locks held by syz-executor/4193:
 #0: ffff88807c32c0e0 (&type->s_umount_key#68){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
 #1: ffff88807c32c650 (sb_internal#4){.+.+}-{0:0}, at: ocfs2_replay_truncate_records fs/ocfs2/alloc.c:5938 [inline]
 #1: ffff88807c32c650 (sb_internal#4){.+.+}-{0:0}, at: __ocfs2_flush_truncate_log+0x49f/0x1110 fs/ocfs2/alloc.c:6052
 #2: ffff888060c810e8 (&journal->j_trans_barrier){.+.+}-{3:3}, at: ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374
 #3: ffff88801d0fa990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12d5/0x1560 fs/jbd2/transaction.c:462

stack backtrace:
CPU: 0 PID: 4193 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 flush_workqueue+0x16a/0x1390 kernel/workqueue.c:2830
 ocfs2_recovery_disable+0x2ba/0x350 fs/ocfs2/journal.c:227
 ocfs2_recovery_exit+0x16/0x50 fs/ocfs2/journal.c:241
 ocfs2_dismount_volume+0x1f1/0x890 fs/ocfs2/super.c:1890
 generic_shutdown_super+0x130/0x300 fs/super.c:475
 kill_block_super+0x7c/0xe0 fs/super.c:1427
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x426/0x4d0 fs/namespace.c:1148
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7efe56d7f0d7
Code: a2 c7 05 1c 26 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffeb8bafe78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007efe56e1330a RCX: 00007efe56d7f0d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeb8baff30
RBP: 00007ffeb8baff30 R08: 00007ffeb8bb0f30 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeb8bb0fc0
R13: 00007efe56e1330a R14: 000000000001ac1b R15: 00007ffeb8bb1000
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/23 04:07 linux-5.15.y c86c4726e7f0 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ocfs2_start_trans
* Struck through repros no longer work on HEAD.