syzbot


possible deadlock in jbd2_log_wait_commit (2)

Status: upstream: reported on 2025/12/20 23:03
Reported-by: syzbot+55a4f0c293a8380cba64@syzkaller.appspotmail.com
First crash: 93d, last: 1d06h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in jbd2_log_wait_commit 4 29 273d 471d 0/3 auto-obsoleted due to no activity on 2025/09/29 15:37
linux-6.1 possible deadlock in jbd2_log_wait_commit 4 1 7d09h 7d09h 0/3 upstream: reported on 2026/03/17 07:14
upstream possible deadlock in jbd2_log_wait_commit ext4 4 C done 429 1095d 1119d 22/29 fixed on 2023/06/08 14:41

Sample crash report:
(syz.1.537,6573,0):__ocfs2_flush_truncate_log:6055 ERROR: status = -12
(syz.1.537,6573,0):ocfs2_sync_fs:405 ERROR: status = -12
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.1.537/6573 is trying to acquire lock:
ffff888078384990 (jbd2_handle){++++}-{0:0}, at: jbd2_log_wait_commit+0x14c/0x4c0 fs/jbd2/journal.c:697

but task is already holding lock:
ffff888078384990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x134c/0x15c0 fs/jbd2/transaction.c:462

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(jbd2_handle);
  lock(jbd2_handle);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

4 locks held by syz.1.537/6573:
 #0: ffff8880232fe0e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
 #1: ffff8880232fe650 (sb_internal#4){.+.+}-{0:0}, at: ocfs2_replay_truncate_records fs/ocfs2/alloc.c:5938 [inline]
 #1: ffff8880232fe650 (sb_internal#4){.+.+}-{0:0}, at: __ocfs2_flush_truncate_log+0x4a5/0x1110 fs/ocfs2/alloc.c:6052
 #2: ffff88805fadfce8 (&journal->j_trans_barrier){.+.+}-{3:3}, at: ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374
 #3: ffff888078384990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x134c/0x15c0 fs/jbd2/transaction.c:462

stack backtrace:
CPU: 0 PID: 6573 Comm: syz.1.537 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 __lock_acquire+0x1236/0x7d10 kernel/locking/lockdep.c:-1
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 jbd2_log_wait_commit+0x168/0x4c0 fs/jbd2/journal.c:697
 ocfs2_sync_fs+0x21d/0x330 fs/ocfs2/super.c:413
 sync_filesystem+0x1be/0x220 fs/sync.c:66
 generic_shutdown_super+0x6b/0x300 fs/super.c:448
 kill_block_super+0x7c/0xe0 fs/super.c:1427
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x42d/0x4e0 fs/namespace.c:1148
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x626/0x20c0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:320
 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1499
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f520eead777
Code: Unable to access opcode bytes at RIP 0x7f520eead74d.
RSP: 002b:00007f520d211120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f520eff7799
RDX: 00007f520d211140 RSI: 00007f520d211270 RDI: 000000000000000b
RBP: 00007f520f08dc99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f520f271128 R14: 00007f520f271090 R15: 00007ffc332d73d8
 </TASK>

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/23 09:45 linux-5.15.y 91d48252ad4b 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2026/02/27 21:47 linux-5.15.y 3330a8d33e08 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2026/02/27 21:44 linux-5.15.y 3330a8d33e08 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2026/02/27 21:44 linux-5.15.y 3330a8d33e08 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2026/01/07 02:26 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2026/01/02 02:37 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2026/01/01 23:05 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2026/01/01 14:32 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2025/12/20 23:12 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2025/12/20 23:02 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
2025/12/20 23:02 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in jbd2_log_wait_commit
* Struck through repros no longer work on HEAD.