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: 239d, last: 3d07h
Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.1193/9228 is trying to acquire lock:
ffff88805531df48 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline]
ffff88805531df48 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: ocfs2_try_to_free_truncate_log+0xb1/0x370 fs/ocfs2/alloc.c:6124
but task is already holding lock:
ffff88805531cda0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_dio_wr_get_block+0x90c/0x1810 fs/ocfs2/aops.c:2227
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_initialize+0x3a9/0xd00 fs/quota/dquot.c:1542
ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
ocfs2_mknod+0xbdc/0x2500 fs/ocfs2/namei.c:311
ocfs2_mkdir+0x1b6/0x4b0 fs/ocfs2/namei.c:659
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
-> #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_alloc_file_blocks+0x378/0xb60 fs/ext4/extents.c:4545
ext4_zero_range+0x661/0xde0 fs/ext4/extents.c:4698
ext4_fallocate+0x542/0x2000 fs/ext4/extents.c:4797
vfs_fallocate+0x57b/0x6f0 fs/open.c:323
ksys_fallocate fs/open.c:346 [inline]
__do_sys_fallocate fs/open.c:354 [inline]
__se_sys_fallocate fs/open.c:352 [inline]
__x64_sys_fallocate+0xbd/0x100 fs/open.c:352
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_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674
mpage_map_one_extent fs/ext4/inode.c:2436 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2489 [inline]
ext4_writepages+0x12aa/0x2e70 fs/ext4/inode.c:2857
do_writepages+0x3c6/0x640 mm/page-writeback.c:2491
__writeback_single_inode+0x153/0x1170 fs/fs-writeback.c:1688
writeback_sb_inodes+0xad5/0x17f0 fs/fs-writeback.c:1979
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2050
wb_writeback+0x484/0xd40 fs/fs-writeback.c:2155
wb_check_background_flush fs/fs-writeback.c:2221 [inline]
wb_do_writeback fs/fs-writeback.c:2309 [inline]
wb_workfn+0xc1c/0xee0 fs/fs-writeback.c:2336
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
-> #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
ocfs2_remount+0x115/0xb40 fs/ocfs2/super.c:611
reconfigure_super+0x224/0x8d0 fs/super.c:977
do_remount fs/namespace.c:2741 [inline]
path_mount+0xcce/0xfb0 fs/namespace.c:3400
do_mount fs/namespace.c:3421 [inline]
__do_sys_mount fs/namespace.c:3629 [inline]
__se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
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
-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{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_write_begin_nolock+0x3306/0x4590 fs/ocfs2/aops.c:1872
ocfs2_dio_wr_get_block+0xba4/0x1810 fs/ocfs2/aops.c:2241
get_more_blocks fs/direct-io.c:659 [inline]
do_direct_IO fs/direct-io.c:947 [inline]
__blockdev_direct_IO+0x171f/0x34c0 fs/direct-io.c:1260
ocfs2_direct_IO+0x233/0x2a0 fs/ocfs2/aops.c:2488
generic_file_direct_write+0x112/0x330 mm/filemap.c:3787
__generic_file_write_iter+0x15f/0x2a0 mm/filemap.c:3945
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_write+0x14d/0x260 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.2.1193/9228:
#0: ffff88805e8545e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
#1: ffff888063462460 (sb_writers#15){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
#2: ffff88805531d108 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline]
#2: ffff88805531d108 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x45a/0x1fc0 fs/ocfs2/file.c:2399
#3: ffff88805531cda0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_dio_wr_get_block+0x90c/0x1810 fs/ocfs2/aops.c:2227
stack backtrace:
CPU: 0 PID: 9228 Comm: syz.2.1193 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_write_begin_nolock+0x3306/0x4590 fs/ocfs2/aops.c:1872
ocfs2_dio_wr_get_block+0xba4/0x1810 fs/ocfs2/aops.c:2241
get_more_blocks fs/direct-io.c:659 [inline]
do_direct_IO fs/direct-io.c:947 [inline]
__blockdev_direct_IO+0x171f/0x34c0 fs/direct-io.c:1260
ocfs2_direct_IO+0x233/0x2a0 fs/ocfs2/aops.c:2488
generic_file_direct_write+0x112/0x330 mm/filemap.c:3787
__generic_file_write_iter+0x15f/0x2a0 mm/filemap.c:3945
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_write+0x14d/0x260 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: 0033:0x7fc14f59e1d9
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:00007fc1504ba028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc14f825fa0 RCX: 00007fc14f59e1d9
RDX: 00000000ffffffd7 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007fc14f635888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc14f826038 R14: 00007fc14f825fa0 R15: 00007ffc9e75dd08
</TASK>
(syz.2.1193,9228,1):ocfs2_dio_end_io:2448 ERROR: Direct IO failed, bytes = -5
Struck through repros no longer work on HEAD.