syzbot
possible deadlock in ocfs2_reflink
Status:
upstream: reported on 2026/07/29 06:41
Reported-by: syzbot+9af42738b9b5aee70008@syzkaller.appspotmail.com
First crash: 6d12h, last: 18h02m
Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.4.433/7712 is trying to acquire lock:
ffff88805c8f3120 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_reflink+0x4cf/0x920 fs/ocfs2/refcounttree.c:4277
but task is already holding lock:
ffff88805c8f31b8 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_reflink+0x4c0/0x920 fs/ocfs2/refcounttree.c:4276
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&oi->ip_xattr_sem){++++}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
ocfs2_init_acl+0x30a/0x770 fs/ocfs2/acl.c:366
ocfs2_mknod+0x1427/0x2310 fs/ocfs2/namei.c:410
ocfs2_create+0x196/0x430 fs/ocfs2/namei.c:674
lookup_open fs/namei.c:3539 [inline]
open_last_lookups fs/namei.c:3607 [inline]
path_openat+0x1705/0x3270 fs/namei.c:3841
do_filp_open+0x1f2/0x430 fs/namei.c:3871
do_sys_openat2+0x134/0x1d0 fs/open.c:1422
do_sys_open fs/open.c:1437 [inline]
__do_sys_open fs/open.c:1445 [inline]
__se_sys_open fs/open.c:1441 [inline]
__x64_sys_open+0x11f/0x140 fs/open.c:1441
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
-> #2 (&journal->j_trans_barrier){.+.+}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
ocfs2_start_trans+0x3a8/0x6f0 fs/ocfs2/journal.c:372
ocfs2_local_alloc_slide_window fs/ocfs2/localalloc.c:1258 [inline]
ocfs2_reserve_local_alloc_bits+0xb39/0x2620 fs/ocfs2/localalloc.c:668
ocfs2_reserve_clusters_with_limit+0x1ba/0xc20 fs/ocfs2/suballoc.c:1184
ocfs2_expand_inline_dir fs/ocfs2/dir.c:2856 [inline]
ocfs2_extend_dir+0x750/0x49b0 fs/ocfs2/dir.c:3201
ocfs2_prepare_dir_for_insert+0x30e7/0x5520 fs/ocfs2/dir.c:4322
ocfs2_mknod+0x831/0x2310 fs/ocfs2/namei.c:294
ocfs2_mkdir+0x196/0x430 fs/ocfs2/namei.c:657
vfs_mkdir+0x2a5/0x470 fs/namei.c:4168
do_mkdirat+0x1dc/0x450 fs/namei.c:4191
__do_sys_mkdirat fs/namei.c:4206 [inline]
__se_sys_mkdirat fs/namei.c:4204 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4204
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
-> #1 (sb_internal#3){.+.+}-{0:0}:
__lock_release kernel/locking/lockdep.c:5468 [inline]
lock_release+0x332/0x8c0 kernel/locking/lockdep.c:5774
up_write+0x2d/0x410 kernel/locking/rwsem.c:1625
inode_unlock include/linux/fs.h:809 [inline]
ocfs2_free_ac_resource fs/ocfs2/suballoc.c:126 [inline]
ocfs2_free_alloc_context+0x97/0x1a0 fs/ocfs2/suballoc.c:140
ocfs2_write_begin_nolock+0x43f6/0x4480 fs/ocfs2/aops.c:1827
ocfs2_write_begin+0x1bb/0x310 fs/ocfs2/aops.c:1906
generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4036
ocfs2_file_write_iter+0x1724/0x1ef0 fs/ocfs2/file.c:2468
call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x474/0x9a0 fs/read_write.c:584
ksys_write+0x151/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
-> #0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137
lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
down_write+0x97/0x200 kernel/locking/rwsem.c:1573
ocfs2_reflink+0x4cf/0x920 fs/ocfs2/refcounttree.c:4277
ocfs2_vfs_reflink+0x333/0x450 fs/ocfs2/refcounttree.c:4404
ocfs2_reflink_ioctl+0x3a0/0x450 fs/ocfs2/refcounttree.c:4444
ocfs2_ioctl+0x5b9/0x7e0 fs/ocfs2/ioctl.c:923
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 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_file_ip_alloc_sem_key --> &journal->j_trans_barrier --> &oi->ip_xattr_sem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&oi->ip_xattr_sem);
lock(&journal->j_trans_barrier);
lock(&oi->ip_xattr_sem);
lock(&ocfs2_file_ip_alloc_sem_key);
*** DEADLOCK ***
4 locks held by syz.4.433/7712:
#0: ffff88802562a418 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
#1: ffff88805ac22658 (&type->i_mutex_dir_key#10/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline]
#1: ffff88805ac22658 (&type->i_mutex_dir_key#10/1){+.+.}-{3:3}, at: filename_create+0x20f/0x450 fs/namei.c:3937
#2: ffff88805c8f3498 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#2: ffff88805c8f3498 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: ocfs2_vfs_reflink+0x2f3/0x450 fs/ocfs2/refcounttree.c:4401
#3: ffff88805c8f31b8 (&oi->ip_xattr_sem){++++}-{3:3}, at: ocfs2_reflink+0x4c0/0x920 fs/ocfs2/refcounttree.c:4276
stack backtrace:
CPU: 0 PID: 7712 Comm: syz.4.433 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137
lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
down_write+0x97/0x200 kernel/locking/rwsem.c:1573
ocfs2_reflink+0x4cf/0x920 fs/ocfs2/refcounttree.c:4277
ocfs2_vfs_reflink+0x333/0x450 fs/ocfs2/refcounttree.c:4404
ocfs2_reflink_ioctl+0x3a0/0x450 fs/ocfs2/refcounttree.c:4444
ocfs2_ioctl+0x5b9/0x7e0 fs/ocfs2/ioctl.c:923
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe66f19e019
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:00007fe670141028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe66f425fa0 RCX: 00007fe66f19e019
RDX: 00002000000001c0 RSI: 0000000040186f04 RDI: 0000000000000004
RBP: 00007fe66f23500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe66f426038 R14: 00007fe66f425fa0 R15: 00007fff95c39ec8
</TASK>
(syz.4.433,7712,0):ocfs2_check_dir_entry:325 ERROR: bad entry in directory #72: rec_len is smaller than minimal - offset=0, inode=1099511627848, rec_len=12, name_len=0
(syz.4.433,7712,0):__ocfs2_delete_entry:1162 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_orphan_del:2389 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_orphan_del:2404 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_mv_orphaned_inode_to_new:2863 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_mv_orphaned_inode_to_new:2909 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_reflink:4311 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_check_dir_entry:325 ERROR: bad entry in directory #72: rec_len is smaller than minimal - offset=0, inode=1099511627848, rec_len=12, name_len=0
(syz.4.433,7712,0):__ocfs2_delete_entry:1162 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_orphan_del:2389 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_orphan_del:2404 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_remove_inode:709 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_wipe_inode:854 ERROR: status = -5
(syz.4.433,7712,0):ocfs2_delete_inode:1115 ERROR: status = -5
Struck through repros no longer work on HEAD.