syzbot


possible deadlock in wait_transaction_locked

Status: upstream: reported on 2026/01/20 15:21
Reported-by: syzbot+6edd366fa6c02b001539@syzkaller.appspotmail.com
First crash: 147d, last: 11h47m
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in wait_transaction_locked ext4 4 3 740d 759d 0/29 auto-obsoleted due to no activity on 2024/09/14 08:21
linux-6.6 possible deadlock in wait_transaction_locked 4 21 5d05h 144d 0/2 upstream: reported on 2026/01/23 09:44
upstream possible deadlock in wait_transaction_locked (3) ext4 prio:high 4 C error 477 now 168d 0/29 upstream: reported C repro on 2025/12/30 11:48
upstream possible deadlock in wait_transaction_locked (2) ext4 4 1 523d 519d 0/29 auto-obsoleted due to no activity on 2025/04/18 23:41
linux-6.1 possible deadlock in wait_transaction_locked 4 C 146 15h30m 155d 0/3 upstream: reported C repro on 2026/01/12 10:36

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:1/144 is trying to acquire lock:
ffff8880775d2990 (jbd2_handle){++++}-{0:0}, at: wait_transaction_locked+0x19f/0x270 fs/jbd2/transaction.c:178

but task is already holding lock:
ffff88805ff25ce8 (&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_modify_bh+0xe0/0x4c0 fs/ocfs2/quota_local.c:101
       ocfs2_local_read_info+0x13c8/0x1750 fs/ocfs2/quota_local.c:764
       dquot_load_quota_sb+0x756/0xac0 fs/quota/dquot.c:2485
       dquot_load_quota_inode+0x2d8/0x5d0 fs/quota/dquot.c:2522
       ocfs2_enable_quotas+0x1c5/0x490 fs/ocfs2/super.c:927
       ocfs2_fill_super+0x3cd2/0x50f0 fs/ocfs2/super.c:1140
       mount_bdev+0x287/0x3c0 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+0x24a/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

-> #4 (sb_internal#5){.+.+}-{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_acquire_dquot+0x688/0xb10 fs/ocfs2/quota_global.c:848
       dqget+0x72b/0xc30 fs/quota/dquot.c:1010
       __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1539
       ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
       ocfs2_mknod+0x8ab/0x2510 fs/ocfs2/namei.c:310
       ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:674
       lookup_open fs/namei.c:3470 [inline]
       open_last_lookups fs/namei.c:3540 [inline]
       path_openat+0x11db/0x2fa0 fs/namei.c:3747
       do_filp_open+0x1e2/0x410 fs/namei.c:3777
       do_sys_openat2+0x150/0x4b0 fs/open.c:1255
       do_sys_open fs/open.c:1271 [inline]
       __do_sys_openat fs/open.c:1287 [inline]
       __se_sys_openat fs/open.c:1282 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1282
       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_quota_ip_alloc_sem_key){++++}-{3:3}:
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ocfs2_create_local_dquot+0x199/0x1850 fs/ocfs2/quota_local.c:1224
       ocfs2_acquire_dquot+0x7ed/0xb10 fs/ocfs2/quota_global.c:871
       dqget+0x72b/0xc30 fs/quota/dquot.c:1010
       __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1539
       ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
       ocfs2_mknod+0x8ab/0x2510 fs/ocfs2/namei.c:310
       ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:674
       lookup_open fs/namei.c:3470 [inline]
       open_last_lookups fs/namei.c:3540 [inline]
       path_openat+0x11db/0x2fa0 fs/namei.c:3747
       do_filp_open+0x1e2/0x410 fs/namei.c:3777
       do_sys_openat2+0x150/0x4b0 fs/open.c:1255
       do_sys_open fs/open.c:1271 [inline]
       __do_sys_openat fs/open.c:1287 [inline]
       __se_sys_openat fs/open.c:1282 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1282
       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 (&dquot->dq_lock){+.+.}-{3:3}:
       __mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       dquot_commit+0x5a/0x410 fs/quota/dquot.c:532
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6212
       mark_dquot_dirty fs/quota/dquot.c:397 [inline]
       mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:437
       __dquot_alloc_space+0x5d0/0xe20 fs/quota/dquot.c:1774
       dquot_alloc_space_nodirty include/linux/quotaops.h:290 [inline]
       dquot_alloc_space include/linux/quotaops.h:303 [inline]
       dquot_alloc_block include/linux/quotaops.h:327 [inline]
       ext4_mb_new_blocks+0xfb1/0x4820 fs/ext4/mballoc.c:5750
       ext4_ext_map_blocks+0x18ab/0x65e0 fs/ext4/extents.c:4357
       ext4_map_blocks+0x98e/0x1b30 fs/ext4/inode.c:675
       ext4_convert_inline_data_nolock+0x40c/0xcd0 fs/ext4/inline.c:1264
       ext4_convert_inline_data+0x4b9/0x5f0 fs/ext4/inline.c:2098
       ext4_fallocate+0xf4/0x1ed0 fs/ext4/extents.c:4775
       vfs_fallocate+0x587/0x6f0 fs/open.c:308
       ksys_fallocate fs/open.c:331 [inline]
       __do_sys_fallocate fs/open.c:339 [inline]
       __se_sys_fallocate fs/open.c:337 [inline]
       __x64_sys_fallocate+0xbd/0x100 fs/open.c:337
       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

-> #1 (&ei->i_data_sem){++++}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ext4_map_blocks+0x33c/0x1b30 fs/ext4/inode.c:600
       ext4_append+0x232/0x560 fs/ext4/namei.c:75
       ext4_init_new_dir+0x2a2/0x940 fs/ext4/namei.c:3030
       ext4_mkdir+0x4fb/0xce0 fs/ext4/namei.c:3076
       vfs_mkdir+0x387/0x570 fs/namei.c:4073
       do_mkdirat+0x1df/0x5b0 fs/namei.c:4098
       __do_sys_mkdir fs/namei.c:4118 [inline]
       __se_sys_mkdir fs/namei.c:4116 [inline]
       __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4116
       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

-> #0 (jbd2_handle){++++}-{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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       wait_transaction_locked+0x1bb/0x270 fs/jbd2/transaction.c:178
       add_transaction_credits+0x103/0xc80 fs/jbd2/transaction.c:242
       start_this_handle+0x74d/0x15c0 fs/jbd2/transaction.c:423
       jbd2__journal_start+0x2b7/0x5a0 fs/jbd2/transaction.c:521
       jbd2_journal_start+0x26/0x30 fs/jbd2/transaction.c:560
       ocfs2_start_trans+0x3b2/0x6f0 fs/ocfs2/journal.c:376
       ocfs2_release_dquot+0x497/0xb50 fs/ocfs2/quota_global.c:749
       quota_release_workfn+0x35e/0x610 fs/quota/dquot.c:872
       process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
       worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
       kthread+0x436/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

other info that might help us debug this:

Chain exists of:
  jbd2_handle --> sb_internal#5 --> &journal->j_trans_barrier

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&journal->j_trans_barrier);
                               lock(sb_internal#5);
                               lock(&journal->j_trans_barrier);
  lock(jbd2_handle);

 *** DEADLOCK ***

7 locks held by kworker/u4:1/144:
 #0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000169fd00 ((quota_release_work).work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff8880206e82a8 (&dquot->dq_lock){+.+.}-{3:3}, at: ocfs2_release_dquot+0x26a/0xb50 fs/ocfs2/quota_global.c:729
 #3: ffff88801c27ed88 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #3: ffff88801c27ed88 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#4){+.+.}-{3:3}, at: ocfs2_lock_global_qf+0x1d7/0x290 fs/ocfs2/quota_global.c:313
 #4: ffff88801c27ea20 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_lock_global_qf+0x1fe/0x290 fs/ocfs2/quota_global.c:314
 #5: ffff88802b202650 (sb_internal#5){.+.+}-{0:0}, at: ocfs2_release_dquot+0x497/0xb50 fs/ocfs2/quota_global.c:749
 #6: ffff88805ff25ce8 (&journal->j_trans_barrier){.+.+}-{3:3}, at: ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374

stack backtrace:
CPU: 0 PID: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound quota_release_workfn
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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 wait_transaction_locked+0x1bb/0x270 fs/jbd2/transaction.c:178
 add_transaction_credits+0x103/0xc80 fs/jbd2/transaction.c:242
 start_this_handle+0x74d/0x15c0 fs/jbd2/transaction.c:423
 jbd2__journal_start+0x2b7/0x5a0 fs/jbd2/transaction.c:521
 jbd2_journal_start+0x26/0x30 fs/jbd2/transaction.c:560
 ocfs2_start_trans+0x3b2/0x6f0 fs/ocfs2/journal.c:376
 ocfs2_release_dquot+0x497/0xb50 fs/ocfs2/quota_global.c:749
 quota_release_workfn+0x35e/0x610 fs/quota/dquot.c:872
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (101):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/16 07:52 linux-5.15.y dc027a595035 50bb0618 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/06/15 04:25 linux-5.15.y dc027a595035 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/06/10 23:50 linux-5.15.y dc027a595035 b754d2d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/05/20 23:27 linux-5.15.y 93741761e5e3 41b8c833 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/05/20 11:37 linux-5.15.y 93741761e5e3 62fb93a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/05/10 01:33 linux-5.15.y de8dfb3f0278 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/05/09 19:35 linux-5.15.y de8dfb3f0278 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/05/02 12:10 linux-5.15.y ef251c45f1cd a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/30 14:26 linux-5.15.y ef251c45f1cd a7464baf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/28 01:00 linux-5.15.y b9d57c40a767 ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/26 07:00 linux-5.15.y b9d57c40a767 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/25 05:24 linux-5.15.y b9d57c40a767 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/23 15:06 linux-5.15.y b9d57c40a767 4c3406dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/23 04:42 linux-5.15.y b9d57c40a767 b10da5ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/21 20:13 linux-5.15.y b9d57c40a767 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/21 18:01 linux-5.15.y b9d57c40a767 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/15 13:32 linux-5.15.y 91d48252ad4b c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/14 04:05 linux-5.15.y 91d48252ad4b 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/14 02:25 linux-5.15.y 91d48252ad4b 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/13 19:24 linux-5.15.y 91d48252ad4b 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/13 13:51 linux-5.15.y 91d48252ad4b 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/13 10:19 linux-5.15.y 91d48252ad4b 9530ccf9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/08 20:54 linux-5.15.y 91d48252ad4b d9b7f621 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/07 14:59 linux-5.15.y 91d48252ad4b 628666c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/07 12:17 linux-5.15.y 91d48252ad4b 628666c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/07 08:49 linux-5.15.y 91d48252ad4b 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/05 06:41 linux-5.15.y 91d48252ad4b 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/03 02:20 linux-5.15.y 91d48252ad4b 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/02 12:37 linux-5.15.y 91d48252ad4b 91bc79b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/02 10:16 linux-5.15.y 91d48252ad4b 91bc79b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/02 02:59 linux-5.15.y 91d48252ad4b 0cb124d5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/02 00:22 linux-5.15.y 91d48252ad4b 0cb124d5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/04/01 00:47 linux-5.15.y 91d48252ad4b fb8b2c26 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/27 06:11 linux-5.15.y 91d48252ad4b 766b6434 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/25 23:08 linux-5.15.y 91d48252ad4b c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/25 04:15 linux-5.15.y 91d48252ad4b 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/24 22:27 linux-5.15.y 91d48252ad4b 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/24 15:38 linux-5.15.y 91d48252ad4b 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/24 00:25 linux-5.15.y 91d48252ad4b baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/23 14:27 linux-5.15.y 91d48252ad4b 4933dba2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/17 20:41 linux-5.15.y 91d48252ad4b c8810548 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/03/11 20:39 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/01/20 15:20 linux-5.15.y 9eec9a14ee10 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
* Struck through repros no longer work on HEAD.