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: 3d07h, last: 3d07h
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 453d 449d 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 3d22h 3d22h 0/3 upstream: reported on 2026/03/06 19:37
upstream possible deadlock in ocfs2_try_to_free_truncate_log (2) ocfs2 4 83 4d19h 325d 0/29 upstream: reported on 2025/04/19 11:02

Sample crash report:
(syz.4.2293,14438,1):ocfs2_block_check_validate:402 ERROR: CRC32 failed: stored: 0xb3775c19, computed 0x2dd1c265. Applying ECC.
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,4) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.4.2293/14438 is trying to acquire lock:
ffff88804e9cd108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff88804e9cd108 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: ocfs2_try_to_free_truncate_log+0xb1/0x350 fs/ocfs2/alloc.c:6124

but task is already holding lock:
ffff88804e9fcda0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x19f/0x320 fs/ocfs2/aops.c:1902

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+0x778/0xeb0 fs/quota/dquot.c:988
       __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517
       ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
       ocfs2_mknod+0x8c8/0x25b0 fs/ocfs2/namei.c:310
       ocfs2_create+0x1b6/0x4b0 fs/ocfs2/namei.c:674
       lookup_open fs/namei.c:3490 [inline]
       open_last_lookups fs/namei.c:3558 [inline]
       path_openat+0x1181/0x2ee0 fs/namei.c:3788
       do_filp_open+0x1f1/0x430 fs/namei.c:3818
       do_sys_openat2+0x150/0x4b0 fs/open.c:1320
       do_sys_open fs/open.c:1336 [inline]
       __do_sys_openat fs/open.c:1352 [inline]
       __se_sys_openat fs/open.c:1347 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1347
       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:507
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6811
       mark_dquot_dirty fs/quota/dquot.c:372 [inline]
       mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412
       __dquot_alloc_space+0x5fc/0xe60 fs/quota/dquot.c:1752
       dquot_alloc_space_nodirty include/linux/quotaops.h:300 [inline]
       dquot_alloc_space include/linux/quotaops.h:313 [inline]
       dquot_alloc_block include/linux/quotaops.h:337 [inline]
       ext4_mb_new_blocks+0xf8d/0x4760 fs/ext4/mballoc.c:5736
       ext4_ext_map_blocks+0x195b/0x6810 fs/ext4/extents.c:4346
       ext4_map_blocks+0x9de/0x1b70 fs/ext4/inode.c:679
       ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:890
       ext4_bread+0x26/0x170 fs/ext4/inode.c:946
       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_write+0x36/0x60 kernel/locking/rwsem.c:1573
       ext4_truncate+0x999/0x1240 fs/ext4/inode.c:4290
       ext4_setattr+0x10cb/0x19f0 fs/ext4/inode.c:5649
       notify_change+0xc74/0xf40 fs/attr.c:499
       do_truncate+0x1ac/0x240 fs/open.c:65
       do_sys_ftruncate+0x312/0x3c0 fs/open.c:193
       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 fs/ocfs2/alloc.c:6076 [inline]
       ocfs2_truncate_log_worker+0x9f/0x190 fs/ocfs2/alloc.c:6089
       process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
       worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
       kthread+0x29d/0x330 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{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_write_begin_nolock+0x1b70/0x44f0 fs/ocfs2/aops.c:1740
       ocfs2_write_begin+0x1c2/0x320 fs/ocfs2/aops.c:1904
       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_write+0x14c/0x250 fs/read_write.c:637
       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]#7 --> &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]#7);

 *** DEADLOCK ***

4 locks held by syz.4.2293/14438:
 #0: ffff88802e6294e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
 #1: ffff888018ed4460 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x26b/0xa30 fs/read_write.c:580
 #2: ffff88804e9fd108 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #2: ffff88804e9fd108 (&sb->s_type->i_mutex_key#29){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x448/0x1f00 fs/ocfs2/file.c:2399
 #3: ffff88804e9fcda0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x19f/0x320 fs/ocfs2/aops.c:1902

stack backtrace:
CPU: 1 PID: 14438 Comm: syz.4.2293 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e 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_write_begin_nolock+0x1b70/0x44f0 fs/ocfs2/aops.c:1740
 ocfs2_write_begin+0x1c2/0x320 fs/ocfs2/aops.c:1904
 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_write+0x14c/0x250 fs/read_write.c:637
 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: 0033:0x7fd34679c799
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:00007fd347661028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd346a15fa0 RCX: 00007fd34679c799
RDX: 000000000208e24b RSI: 0000200000000040 RDI: 0000000000000006
RBP: 00007fd346832bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd346a16038 R14: 00007fd346a15fa0 R15: 00007fff095d1428
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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
* Struck through repros no longer work on HEAD.