syzbot


possible deadlock in ocfs2_try_to_free_truncate_log

Status: upstream: reported on 2026/03/06 19:37
Reported-by: syzbot+5ebf0c5ecb5e47f3a0fe@syzkaller.appspotmail.com
First crash: 5d01h, last: 5d01h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 possible deadlock in ocfs2_try_to_free_truncate_log 4 1 4d09h 4d09h 0/3 upstream: reported on 2026/03/07 10:54
upstream possible deadlock in ocfs2_try_to_free_truncate_log ocfs2 4 1 454d 450d 0/29 auto-obsoleted due to no activity on 2025/03/22 03:11
upstream possible deadlock in ocfs2_try_to_free_truncate_log (2) ocfs2 4 83 5d22h 326d 0/29 upstream: reported on 2025/04/19 11:02

Sample crash report:
(syz.3.167,4946,1):ocfs2_block_check_validate:402 ERROR: CRC32 failed: stored: 0xb3775c19, computed 0x2dd1c265. Applying ECC.
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,3) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.167/4946 is trying to acquire lock:
ffff888074bf89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff888074bf89c8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: ocfs2_try_to_free_truncate_log+0xb1/0x350 fs/ocfs2/alloc.c:6122

but task is already holding lock:
ffff888060980660 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x198/0x310 fs/ocfs2/aops.c:1903

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+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+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+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 (&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:507
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6210
       mark_dquot_dirty fs/quota/dquot.c:372 [inline]
       mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412
       __dquot_free_space+0x7ca/0xb90 fs/quota/dquot.c:1942
       dquot_free_space_nodirty include/linux/quotaops.h:376 [inline]
       dquot_free_space include/linux/quotaops.h:381 [inline]
       dquot_free_block include/linux/quotaops.h:392 [inline]
       ext4_mb_clear_bb fs/ext4/mballoc.c:6165 [inline]
       ext4_free_blocks+0x1b2b/0x24d0 fs/ext4/mballoc.c:6295
       ext4_remove_blocks fs/ext4/extents.c:2507 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2691 [inline]
       ext4_ext_remove_space+0x211e/0x42b0 fs/ext4/extents.c:2939
       ext4_ext_truncate+0x192/0x240 fs/ext4/extents.c:4479
       ext4_truncate+0xa09/0x10f0 fs/ext4/inode.c:4256
       ext4_setattr+0xffe/0x19e0 fs/ext4/inode.c:5601
       notify_change+0xbcd/0xee0 fs/attr.c:505
       do_truncate+0x1ac/0x240 fs/open.c:65
       handle_truncate fs/namei.c:3273 [inline]
       do_open fs/namei.c:3620 [inline]
       path_openat+0x2922/0x2fa0 fs/namei.c:3750
       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 (&ei->i_data_sem){++++}-{3:3}:
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ext4_map_blocks+0x8bf/0x1b30 fs/ext4/inode.c:666
       mpage_map_one_extent fs/ext4/inode.c:2408 [inline]
       mpage_map_and_submit_extent fs/ext4/inode.c:2461 [inline]
       ext4_writepages+0x135b/0x2df0 fs/ext4/inode.c:2829
       do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
       __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
       writeback_sb_inodes+0xa4e/0x1680 fs/fs-writeback.c:1940
       __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
       wb_writeback+0x46f/0xbe0 fs/fs-writeback.c:2116
       wb_check_background_flush fs/fs-writeback.c:2182 [inline]
       wb_do_writeback fs/fs-writeback.c:2270 [inline]
       wb_workfn+0xbd6/0xf20 fs/fs-writeback.c:2298
       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

-> #1 (jbd2_handle){++++}-{0:0}:
       jbd2_journal_lock_updates+0xa4/0x390 fs/jbd2/transaction.c:881
       __ocfs2_flush_truncate_log+0x2ba/0x1110 fs/ocfs2/alloc.c:6027
       ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6074
       ocfs2_sync_fs+0x119/0x330 fs/ocfs2/super.c:403
       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
       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

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}:
       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
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       inode_lock include/linux/fs.h:787 [inline]
       ocfs2_try_to_free_truncate_log+0xb1/0x350 fs/ocfs2/alloc.c:6122
       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+0x1d17/0x4400 fs/ocfs2/aops.c:1741
       ocfs2_write_begin+0x1b9/0x310 fs/ocfs2/aops.c:1905
       generic_perform_write+0x2b6/0x550 mm/filemap.c:3785
       __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912
       ocfs2_file_write_iter+0x1670/0x1e70 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+0x745/0xd60 fs/read_write.c:594
       ksys_write+0x152/0x260 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

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.3.167/4946:
 #0: ffff8880778a74f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff888076b8a460 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x295/0xd60 fs/read_write.c:590
 #2: ffff8880609809c8 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #2: ffff8880609809c8 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x436/0x1e70 fs/ocfs2/file.c:2402
 #3: ffff888060980660 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x198/0x310 fs/ocfs2/aops.c:1903

stack backtrace:
CPU: 1 PID: 4946 Comm: syz.3.167 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
 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
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 inode_lock include/linux/fs.h:787 [inline]
 ocfs2_try_to_free_truncate_log+0xb1/0x350 fs/ocfs2/alloc.c:6122
 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+0x1d17/0x4400 fs/ocfs2/aops.c:1741
 ocfs2_write_begin+0x1b9/0x310 fs/ocfs2/aops.c:1905
 generic_perform_write+0x2b6/0x550 mm/filemap.c:3785
 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912
 ocfs2_file_write_iter+0x1670/0x1e70 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+0x745/0xd60 fs/read_write.c:594
 ksys_write+0x152/0x260 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
RIP: 0033:0x7f87213d5799
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:00007f871f62f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f872164efa0 RCX: 00007f87213d5799
RDX: 000000000208e24b RSI: 0000200000000040 RDI: 0000000000000007
RBP: 00007f872146bbd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f872164f038 R14: 00007f872164efa0 R15: 00007ffe7b098628
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/06 19:36 linux-5.15.y 91d48252ad4b 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in ocfs2_try_to_free_truncate_log
* Struck through repros no longer work on HEAD.