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: 217d, last: 3d14h
Sample crash report:
ocfs2: Mounting device (7,5) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.5.14424/6602 is trying to acquire lock:
ffff8880479aa648 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline]
ffff8880479aa648 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2){+.+.}-{3:3}, at: ocfs2_try_to_free_truncate_log+0xb1/0x370 fs/ocfs2/alloc.c:6124
but task is already holding lock:
ffff8880479aea20 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x194/0x310 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+0x19a/0x1900 fs/ocfs2/quota_local.c:1224
ocfs2_acquire_dquot+0x7e6/0xb80 fs/ocfs2/quota_global.c:871
dqget+0x713/0xbb0 fs/quota/dquot.c:1013
dquot_set_dqblk+0x27/0xfb0 fs/quota/dquot.c:2858
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/0xae0 kernel/locking/mutex.c:747
dquot_commit+0x5a/0x410 fs/quota/dquot.c:535
ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817
mark_dquot_dirty fs/quota/dquot.c:400 [inline]
mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440
__dquot_alloc_space+0x5f6/0xe50 fs/quota/dquot.c:1777
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+0xf55/0x44d0 fs/ext4/mballoc.c:5740
ext4_ext_map_blocks+0x18d1/0x6640 fs/ext4/extents.c:4361
ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681
ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892
ext4_bread+0x26/0x170 fs/ext4/inode.c:948
ext4_append+0x2bb/0x560 fs/ext4/namei.c:83
ext4_init_new_dir+0x2b8/0x550 fs/ext4/namei.c:3032
ext4_mkdir+0x4c3/0xc90 fs/ext4/namei.c:3078
vfs_mkdir+0x386/0x570 fs/namei.c:4157
do_mkdirat+0x1d8/0x440 fs/namei.c:4182
__do_sys_mkdirat fs/namei.c:4197 [inline]
__se_sys_mkdirat fs/namei.c:4195 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4195
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+0x338/0x1a90 fs/ext4/inode.c:606
ext4_append+0x22d/0x560 fs/ext4/namei.c:75
ext4_init_new_dir+0x2b8/0x550 fs/ext4/namei.c:3032
ext4_mkdir+0x4c3/0xc90 fs/ext4/namei.c:3078
vfs_mkdir+0x386/0x570 fs/namei.c:4157
do_mkdirat+0x1d8/0x440 fs/namei.c:4182
__do_sys_mkdir fs/namei.c:4202 [inline]
__se_sys_mkdir fs/namei.c:4200 [inline]
__x64_sys_mkdir+0x6a/0x80 fs/namei.c:4200
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:1481
deactivate_locked_super+0x93/0xf0 fs/super.c:332
cleanup_mnt+0x471/0x4f0 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:180
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213
__syscall_exit_to_user_mode_work kernel/entry/common.c:295 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:306
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]#2){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3162 [inline]
check_prevs_add kernel/locking/lockdep.c:3281 [inline]
validate_chain kernel/locking/lockdep.c:3897 [inline]
__lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171
lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:764 [inline]
ocfs2_try_to_free_truncate_log+0xb1/0x370 fs/ocfs2/alloc.c:6124
ocfs2_reserve_clusters_with_limit+0x48a/0xc10 fs/ocfs2/suballoc.c:1202
ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1245 [inline]
ocfs2_lock_allocators+0x2ce/0x5f0 fs/ocfs2/suballoc.c:2701
ocfs2_extend_allocation+0x3fe/0x1940 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+0x1e8c/0x4590 fs/ocfs2/aops.c:1689
ocfs2_write_begin+0x1b7/0x310 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+0x1731/0x1fc0 fs/ocfs2/file.c:2469
call_write_iter include/linux/fs.h:2271 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x482/0x9a0 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+0x194/0x220 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]#2 --> &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]#2);
*** DEADLOCK ***
3 locks held by syz.5.14424/6602:
#0: ffff88802d308460 (sb_writers#32){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#1: ffff8880479aed88 (&sb->s_type->i_mutex_key#45){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline]
#1: ffff8880479aed88 (&sb->s_type->i_mutex_key#45){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x45a/0x1fc0 fs/ocfs2/file.c:2399
#2: ffff8880479aea20 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x194/0x310 fs/ocfs2/aops.c:1904
stack backtrace:
CPU: 0 PID: 6602 Comm: syz.5.14424 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
check_noncircular+0x2f8/0x400 kernel/locking/lockdep.c:2215
check_prev_add kernel/locking/lockdep.c:3162 [inline]
check_prevs_add kernel/locking/lockdep.c:3281 [inline]
validate_chain kernel/locking/lockdep.c:3897 [inline]
__lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171
lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790
down_write+0x36/0x60 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:764 [inline]
ocfs2_try_to_free_truncate_log+0xb1/0x370 fs/ocfs2/alloc.c:6124
ocfs2_reserve_clusters_with_limit+0x48a/0xc10 fs/ocfs2/suballoc.c:1202
ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1245 [inline]
ocfs2_lock_allocators+0x2ce/0x5f0 fs/ocfs2/suballoc.c:2701
ocfs2_extend_allocation+0x3fe/0x1940 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+0x1e8c/0x4590 fs/ocfs2/aops.c:1689
ocfs2_write_begin+0x1b7/0x310 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+0x1731/0x1fc0 fs/ocfs2/file.c:2469
call_write_iter include/linux/fs.h:2271 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x482/0x9a0 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+0x194/0x220 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: 0033:0x7f1a7259e199
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:00007f1a73489028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f1a72825fa0 RCX: 00007f1a7259e199
RDX: 0000000000000001 RSI: 0000200000000340 RDI: 0000000000000004
RBP: 00007f1a726358e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000400b5e R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1a72826038 R14: 00007f1a72825fa0 R15: 00007fff31379aa8
</TASK>
Struck through repros no longer work on HEAD.