syzbot


possible deadlock in ocfs2_try_to_free_truncate_log

Status: upstream: reported on 2026/03/07 10:54
Reported-by: syzbot+c979b75f08dd2365291a@syzkaller.appspotmail.com
First crash: 107d, last: 4d04h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ocfs2_try_to_free_truncate_log ocfs2 4 1 557d 553d 0/29 auto-obsoleted due to no activity on 2025/03/22 03:11
linux-5.15 possible deadlock in ocfs2_try_to_free_truncate_log 4 1 107d 107d 0/3 auto-obsoleted due to no activity on 2026/06/14 19:37
upstream possible deadlock in ocfs2_try_to_free_truncate_log (2) prio:high ocfs2 4 104 10d 429d 0/29 upstream: reported on 2025/04/19 11:02

Sample crash report:
ocfs2: Mounting device (7,3) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.104/5067 is trying to acquire lock:
ffff88807020d108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff88807020d108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}, at: ocfs2_try_to_free_truncate_log+0xb1/0x350 fs/ocfs2/alloc.c:6124

but task is already holding lock:
ffff88807020bf60 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x19f/0x320 fs/ocfs2/aops.c:1904

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       ocfs2_create_local_dquot+0x1a5/0x18e0 fs/ocfs2/quota_local.c:1224
       ocfs2_acquire_dquot+0x7c6/0xb20 fs/ocfs2/quota_global.c:871
       dqget+0x72b/0xc30 fs/quota/dquot.c:1010
       dquot_set_dqblk+0x27/0xf90 fs/quota/dquot.c:2855
       quota_setquota+0x4d6/0x590 fs/quota/quota.c:310
       __do_sys_quotactl fs/quota/quota.c:960 [inline]
       __se_sys_quotactl+0x28b/0x6f0 fs/quota/quota.c:916
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #3 (&dquot->dq_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12d/0xaf0 kernel/locking/mutex.c:747
       dquot_commit+0x5a/0x410 fs/quota/dquot.c:532
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817
       mark_dquot_dirty fs/quota/dquot.c:397 [inline]
       mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:437
       __dquot_alloc_space+0x5fc/0xe60 fs/quota/dquot.c:1774
       dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline]
       dquot_alloc_space include/linux/quotaops.h:306 [inline]
       dquot_alloc_block include/linux/quotaops.h:330 [inline]
       ext4_mb_new_blocks+0xfc4/0x4610 fs/ext4/mballoc.c:5740
       ext4_ext_map_blocks+0x195b/0x6810 fs/ext4/extents.c:4361
       ext4_map_blocks+0x9de/0x1b70 fs/ext4/inode.c:681
       ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:892
       ext4_bread+0x26/0x170 fs/ext4/inode.c:948
       ext4_append+0x2be/0x560 fs/ext4/namei.c:83
       ext4_init_new_dir+0x2b8/0x570 fs/ext4/namei.c:3030
       ext4_mkdir+0x4fb/0xce0 fs/ext4/namei.c:3076
       vfs_mkdir+0x387/0x570 fs/namei.c:4114
       do_mkdirat+0x1d8/0x440 fs/namei.c:4139
       __do_sys_mkdirat fs/namei.c:4154 [inline]
       __se_sys_mkdirat fs/namei.c:4152 [inline]
       __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4152
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (&ei->i_data_sem){++++}-{3:3}:
       down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520
       ext4_map_blocks+0x323/0x1b70 fs/ext4/inode.c:606
       ext4_append+0x232/0x560 fs/ext4/namei.c:75
       ext4_init_new_dir+0x2b8/0x570 fs/ext4/namei.c:3030
       ext4_mkdir+0x4fb/0xce0 fs/ext4/namei.c:3076
       vfs_mkdir+0x387/0x570 fs/namei.c:4114
       do_mkdirat+0x1d8/0x440 fs/namei.c:4139
       __do_sys_mkdir fs/namei.c:4159 [inline]
       __se_sys_mkdir fs/namei.c:4157 [inline]
       __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4157
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (jbd2_handle){++++}-{0:0}:
       jbd2_journal_lock_updates+0xa8/0x390 fs/jbd2/transaction.c:880
       __ocfs2_flush_truncate_log+0x2cf/0x1220 fs/ocfs2/alloc.c:6029
       ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6076
       ocfs2_sync_fs+0x119/0x330 fs/ocfs2/super.c:402
       sync_filesystem+0x1be/0x220 fs/sync.c:66
       generic_shutdown_super+0x6b/0x340 fs/super.c:474
       kill_block_super+0x7c/0xe0 fs/super.c:1470
       deactivate_locked_super+0x93/0xf0 fs/super.c:332
       cleanup_mnt+0x42c/0x4b0 fs/namespace.c:1191
       task_work_run+0x1d0/0x260 kernel/task_work.c:203
       resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
       exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
       __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049
       lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       ocfs2_try_to_free_truncate_log+0xb1/0x350 fs/ocfs2/alloc.c:6124
       ocfs2_reserve_clusters_with_limit+0x48a/0xc10 fs/ocfs2/suballoc.c:1180
       ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
       ocfs2_lock_allocators+0x2d5/0x5f0 fs/ocfs2/suballoc.c:2679
       ocfs2_extend_allocation+0x3fe/0x1930 fs/ocfs2/file.c:585
       ocfs2_extend_no_holes+0x206/0x4b0 fs/ocfs2/file.c:1027
       ocfs2_expand_nonsparse_inode+0x15d/0x450 fs/ocfs2/aops.c:1623
       ocfs2_write_begin_nolock+0x1e52/0x44f0 fs/ocfs2/aops.c:1689
       ocfs2_write_begin+0x1c2/0x320 fs/ocfs2/aops.c:1906
       generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
       __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
       ocfs2_file_write_iter+0x1660/0x1f00 fs/ocfs2/file.c:2469
       call_write_iter include/linux/fs.h:2265 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x4b1/0xa30 fs/read_write.c:584
       ksys_pwrite64 fs/read_write.c:699 [inline]
       __do_sys_pwrite64 fs/read_write.c:709 [inline]
       __se_sys_pwrite64 fs/read_write.c:706 [inline]
       __x64_sys_pwrite64+0x197/0x220 fs/read_write.c:706
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6 --> &dquot->dq_lock --> &ocfs2_quota_ip_alloc_sem_key

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ocfs2_quota_ip_alloc_sem_key);
                               lock(&dquot->dq_lock);
                               lock(&ocfs2_quota_ip_alloc_sem_key);
  lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#6);

 *** DEADLOCK ***

3 locks held by syz.3.104/5067:
 #0: ffff888074814460 (sb_writers#13){.+.+}-{0:0}, at: vfs_write+0x26b/0xa30 fs/read_write.c:580
 #1: ffff88807020c2c8 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff88807020c2c8 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x448/0x1f00 fs/ocfs2/file.c:2399
 #2: ffff88807020bf60 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x19f/0x320 fs/ocfs2/aops.c:1904

stack backtrace:
CPU: 0 PID: 5067 Comm: syz.3.104 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 down_write+0x36/0x60 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:758 [inline]
 ocfs2_try_to_free_truncate_log+0xb1/0x350 fs/ocfs2/alloc.c:6124
 ocfs2_reserve_clusters_with_limit+0x48a/0xc10 fs/ocfs2/suballoc.c:1180
 ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
 ocfs2_lock_allocators+0x2d5/0x5f0 fs/ocfs2/suballoc.c:2679
 ocfs2_extend_allocation+0x3fe/0x1930 fs/ocfs2/file.c:585
 ocfs2_extend_no_holes+0x206/0x4b0 fs/ocfs2/file.c:1027
 ocfs2_expand_nonsparse_inode+0x15d/0x450 fs/ocfs2/aops.c:1623
 ocfs2_write_begin_nolock+0x1e52/0x44f0 fs/ocfs2/aops.c:1689
 ocfs2_write_begin+0x1c2/0x320 fs/ocfs2/aops.c:1906
 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
 ocfs2_file_write_iter+0x1660/0x1f00 fs/ocfs2/file.c:2469
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4b1/0xa30 fs/read_write.c:584
 ksys_pwrite64 fs/read_write.c:699 [inline]
 __do_sys_pwrite64 fs/read_write.c:709 [inline]
 __se_sys_pwrite64 fs/read_write.c:706 [inline]
 __x64_sys_pwrite64+0x197/0x220 fs/read_write.c:706
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fddac19ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fddad114028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fddac415fa0 RCX: 00007fddac19ce59
RDX: 00000000ffffff07 RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007fddac232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000c61 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fddac416038 R14: 00007fddac415fa0 R15: 00007ffc5d5f6bb8
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/18 09:04 linux-6.1.y 228da13e907e b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_try_to_free_truncate_log
2026/03/07 10:53 linux-6.1.y f2ddafa93a25 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_try_to_free_truncate_log
2026/05/05 02:40 linux-6.1.y 4931e0e1673d a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_try_to_free_truncate_log
* Struck through repros no longer work on HEAD.