syzbot
possible deadlock in ocfs2_remove_btree_range (3)
Status:
upstream: reported on 2026/07/28 02:59
Reported-by: syzbot+5ef4e438a0104b474f2c@syzkaller.appspotmail.com
First crash: 86d, last: 4d12h
Sample crash report:
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,2) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.137/5120 is trying to acquire lock:
ffff888056c1b488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
ffff888056c1b488 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#2){+.+.}-{3:3}, at: ocfs2_remove_btree_range+0x64f/0x15e0 fs/ocfs2/alloc.c:5742
but task is already holding lock:
ffff88805dd1ea20 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x335/0x1540 fs/ocfs2/file.c:467
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+0x199/0x18d0 fs/ocfs2/quota_local.c:1224
ocfs2_acquire_dquot+0x822/0xb30 fs/ocfs2/quota_global.c:871
dqget+0x713/0xbb0 fs/quota/dquot.c:1010
__dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1539
ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
ocfs2_mknod+0x90e/0x2460 fs/ocfs2/namei.c:311
ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:676
lookup_open fs/namei.c:3513 [inline]
open_last_lookups fs/namei.c:3583 [inline]
path_openat+0x120a/0x2fb0 fs/namei.c:3790
do_filp_open+0x1df/0x400 fs/namei.c:3820
do_sys_openat2+0x14b/0x500 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+0x1e5/0x2400 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:532
ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6212
mark_dquot_dirty fs/quota/dquot.c:397 [inline]
mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:437
__dquot_alloc_space+0x5cb/0xe10 fs/quota/dquot.c:1774
dquot_alloc_space_nodirty include/linux/quotaops.h:290 [inline]
dquot_alloc_space include/linux/quotaops.h:303 [inline]
dquot_alloc_block include/linux/quotaops.h:327 [inline]
ext4_mb_new_blocks+0xf80/0x47c0 fs/ext4/mballoc.c:5750
ext4_ext_map_blocks+0x17d1/0x63d0 fs/ext4/extents.c:4372
ext4_map_blocks+0x97f/0x1a50 fs/ext4/inode.c:675
ext4_iomap_alloc fs/ext4/inode.c:3410 [inline]
ext4_iomap_begin+0x800/0xb70 fs/ext4/inode.c:3460
iomap_iter+0x604/0xda0 fs/iomap/iter.c:74
__iomap_dio_rw+0x10e6/0x1ba0 fs/iomap/direct-io.c:589
iomap_dio_rw+0x38/0x90 fs/iomap/direct-io.c:676
ext4_dio_write_iter fs/ext4/file.c:547 [inline]
ext4_file_write_iter+0x12e6/0x1720 fs/ext4/file.c:667
do_iter_readv_writev+0x47d/0x5f0 fs/read_write.c:-1
do_iter_write+0x1f8/0x7a0 fs/read_write.c:855
iter_file_splice_write+0x6be/0xcf0 fs/splice.c:689
do_splice_from fs/splice.c:767 [inline]
direct_splice_actor+0xe1/0x130 fs/splice.c:956
splice_direct_to_actor+0x4e8/0xc00 fs/splice.c:902
do_splice_direct+0x1d4/0x2f0 fs/splice.c:1008
do_sendfile+0x524/0xe30 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1303
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_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
ext4_map_blocks+0x350/0x1a50 fs/ext4/inode.c:600
ext4_append+0x22d/0x560 fs/ext4/namei.c:75
ext4_init_new_dir+0x2a7/0x910 fs/ext4/namei.c:3032
ext4_mkdir+0x4c3/0xc90 fs/ext4/namei.c:3078
vfs_mkdir+0x386/0x570 fs/namei.c:4116
do_mkdirat+0x1dd/0x5c0 fs/namei.c:4141
__do_sys_mkdir fs/namei.c:4161 [inline]
__se_sys_mkdir fs/namei.c:4159 [inline]
__x64_sys_mkdir+0x6a/0x80 fs/namei.c:4159
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
-> #1 (jbd2_handle
){++++}-{0:0}:
jbd2_journal_lock_updates+0xa4/0x390 fs/jbd2/transaction.c:881
__ocfs2_flush_truncate_log+0x2b4/0x1110 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:1438
deactivate_locked_super+0x93/0xf0 fs/super.c:335
cleanup_mnt+0x426/0x4d0 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:184
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217
__syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:310
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]
#2){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3120 [inline]
check_prevs_add kernel/locking/lockdep.c:3239 [inline]
validate_chain kernel/locking/lockdep.c:3855 [inline]
__lock_acquire+0x38f7/0x7d40 kernel/locking/lockdep.c:5120
lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:793 [inline]
ocfs2_remove_btree_range+0x64f/0x15e0 fs/ocfs2/alloc.c:5742
ocfs2_commit_truncate+0xb62/0x1d30 fs/ocfs2/alloc.c:7346
ocfs2_truncate_file+0xd89/0x1540 fs/ocfs2/file.c:505
ocfs2_setattr+0x1545/0x1b40 fs/ocfs2/file.c:1215
notify_change+0xbc6/0xee0 fs/attr.c:505
do_truncate+0x1ac/0x240 fs/open.c:65
handle_truncate fs/namei.c:3316 [inline]
do_open fs/namei.c:3663 [inline]
path_openat+0x293b/0x2fb0 fs/namei.c:3793
do_filp_open+0x1df/0x400 fs/namei.c:3820
do_sys_openat2+0x14b/0x500 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
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.2.137/5120:
#0: ffff888059084460 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
#1: ffff88805dd1ed88
(&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
(&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
#2: ffff88805dd1ea20 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x335/0x1540 fs/ocfs2/file.c:467
stack backtrace:
CPU: 0 PID: 5120 Comm: syz.2.137 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
check_noncircular+0x2f8/0x400 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3120 [inline]
check_prevs_add kernel/locking/lockdep.c:3239 [inline]
validate_chain kernel/locking/lockdep.c:3855 [inline]
__lock_acquire+0x38f7/0x7d40 kernel/locking/lockdep.c:5120
lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:793 [inline]
ocfs2_remove_btree_range+0x64f/0x15e0 fs/ocfs2/alloc.c:5742
ocfs2_commit_truncate+0xb62/0x1d30 fs/ocfs2/alloc.c:7346
ocfs2_truncate_file+0xd89/0x1540 fs/ocfs2/file.c:505
ocfs2_setattr+0x1545/0x1b40 fs/ocfs2/file.c:1215
notify_change+0xbc6/0xee0 fs/attr.c:505
do_truncate+0x1ac/0x240 fs/open.c:65
handle_truncate fs/namei.c:3316 [inline]
do_open fs/namei.c:3663 [inline]
path_openat+0x293b/0x2fb0 fs/namei.c:3793
do_filp_open+0x1df/0x400 fs/namei.c:3820
do_sys_openat2+0x14b/0x500 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
RIP: 0033:0x7fe758896559
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:00007fe756aee028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fe758b1dfa0 RCX: 00007fe758896559
RDX: 000000000000275a RSI: 0000200000015640 RDI: ffffffffffffff9c
RBP: 00007fe75892dab8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe758b1e038 R14: 00007fe758b1dfa0 R15: 00007ffdeb7a6288
</TASK>
kcov: kcov_task_exit: t = ffff888060500000, kcov->t = ffff888060500000
Struck through repros no longer work on HEAD.