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Message-ID: <68d25aa7.a70a0220.1b52b.02a2.GAE@google.com>
Date: Tue, 23 Sep 2025 01:30:31 -0700
From: syzbot <syzbot+322e77eae942c8a32a6c@...kaller.appspotmail.com>
To: jlbec@...lplan.org, joseph.qi@...ux.alibaba.com,
linux-kernel@...r.kernel.org, mark@...heh.com, ocfs2-devel@...ts.linux.dev,
syzkaller-bugs@...glegroups.com
Subject: [syzbot] [ocfs2?] possible deadlock in ocfs2_lock_refcount_tree (3)
Hello,
syzbot found the following issue on:
HEAD commit: c9d61056440c Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=166b0d04580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b8b6789b42526d72
dashboard link: https://syzkaller.appspot.com/bug?extid=322e77eae942c8a32a6c
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4f571468ab6f/disk-c9d61056.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3871c29d58eb/vmlinux-c9d61056.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dbc62ff54c5b/Image-c9d61056.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+322e77eae942c8a32a6c@...kaller.appspotmail.com
debugfs: 'B1DE653C5FFC4D88B33B244AAB9EB3E9' already exists in 'ocfs2'
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.173/7608 is trying to acquire lock:
ffff0000c8a0b898 (&new->rf_sem){+.+.}-{4:4}, at: __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
ffff0000c8a0b898 (&new->rf_sem){+.+.}-{4:4}, at: ocfs2_lock_refcount_tree+0x188/0x924 fs/ocfs2/refcounttree.c:463
but task is already holding lock:
ffff0000f67a22e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}, at: ocfs2_truncate_file+0x30c/0x12f4 fs/ocfs2/file.c:471
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}:
down_write+0x50/0xc0 kernel/locking/rwsem.c:1590
ocfs2_try_remove_refcount_tree+0xb4/0x2d8 fs/ocfs2/refcounttree.c:932
ocfs2_xattr_set+0x460/0xe9c fs/ocfs2/xattr.c:3669
ocfs2_set_acl+0x574/0x628 fs/ocfs2/acl.c:254
ocfs2_iop_set_acl+0x190/0x25c fs/ocfs2/acl.c:286
set_posix_acl fs/posix_acl.c:954 [inline]
vfs_set_acl+0x70c/0x974 fs/posix_acl.c:1133
do_set_acl+0xc8/0x1a8 fs/posix_acl.c:1278
do_setxattr fs/xattr.c:633 [inline]
filename_setxattr+0x268/0x4f8 fs/xattr.c:665
path_setxattrat+0x2e8/0x320 fs/xattr.c:713
__do_sys_setxattr fs/xattr.c:747 [inline]
__se_sys_setxattr fs/xattr.c:743 [inline]
__arm64_sys_setxattr+0xc0/0xdc fs/xattr.c:743
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
-> #4 (&oi->ip_xattr_sem){++++}-{4:4}:
down_read+0x58/0x2f8 kernel/locking/rwsem.c:1537
ocfs2_init_acl+0x258/0x5f0 fs/ocfs2/acl.c:366
ocfs2_mknod+0x1028/0x1cf0 fs/ocfs2/namei.c:413
ocfs2_create+0x190/0x474 fs/ocfs2/namei.c:676
lookup_open fs/namei.c:3708 [inline]
open_last_lookups fs/namei.c:3807 [inline]
path_openat+0x12d8/0x2c40 fs/namei.c:4043
do_filp_open+0x18c/0x36c fs/namei.c:4073
do_sys_openat2+0x11c/0x1b4 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__arm64_sys_openat+0x120/0x158 fs/open.c:1461
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
-> #3 (jbd2_handle){++++}-{0:0}:
start_this_handle+0xe74/0x10dc fs/jbd2/transaction.c:444
jbd2__journal_start+0x288/0x51c fs/jbd2/transaction.c:501
jbd2_journal_start+0x3c/0x4c fs/jbd2/transaction.c:540
ocfs2_start_trans+0x368/0x6b0 fs/ocfs2/journal.c:374
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:685 [inline]
ocfs2_reserve_suballoc_bits+0x630/0x3b9c fs/ocfs2/suballoc.c:834
ocfs2_reserve_new_metadata_blocks+0x368/0x810 fs/ocfs2/suballoc.c:984
ocfs2_mknod+0xbd8/0x1cf0 fs/ocfs2/namei.c:350
ocfs2_create+0x190/0x474 fs/ocfs2/namei.c:676
lookup_open fs/namei.c:3708 [inline]
open_last_lookups fs/namei.c:3807 [inline]
path_openat+0x12d8/0x2c40 fs/namei.c:4043
do_filp_open+0x18c/0x36c fs/namei.c:4073
do_sys_openat2+0x11c/0x1b4 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__arm64_sys_openat+0x120/0x158 fs/open.c:1461
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
-> #2 (&journal->j_trans_barrier){.+.+}-{4:4}:
down_read+0x58/0x2f8 kernel/locking/rwsem.c:1537
ocfs2_start_trans+0x35c/0x6b0 fs/ocfs2/journal.c:372
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:685 [inline]
ocfs2_reserve_suballoc_bits+0x630/0x3b9c fs/ocfs2/suballoc.c:834
ocfs2_reserve_new_metadata_blocks+0x368/0x810 fs/ocfs2/suballoc.c:984
ocfs2_mknod+0xbd8/0x1cf0 fs/ocfs2/namei.c:350
ocfs2_create+0x190/0x474 fs/ocfs2/namei.c:676
lookup_open fs/namei.c:3708 [inline]
open_last_lookups fs/namei.c:3807 [inline]
path_openat+0x12d8/0x2c40 fs/namei.c:4043
do_filp_open+0x18c/0x36c fs/namei.c:4073
do_sys_openat2+0x11c/0x1b4 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__arm64_sys_openat+0x120/0x158 fs/open.c:1461
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
-> #1 (sb_internal#3){.+.+}-{0:0}:
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
__sb_start_write include/linux/fs.h:1799 [inline]
sb_start_intwrite include/linux/fs.h:1982 [inline]
ocfs2_start_trans+0x1f4/0x6b0 fs/ocfs2/journal.c:370
ocfs2_set_refcount_tree+0x1f8/0x624 fs/ocfs2/refcounttree.c:713
ocfs2_reflink_remap_blocks+0x518/0x14b0 fs/ocfs2/refcounttree.c:4663
ocfs2_remap_file_range+0x3fc/0x638 fs/ocfs2/file.c:2740
vfs_copy_file_range+0xb24/0x1058 fs/read_write.c:1591
__do_sys_copy_file_range fs/read_write.c:1677 [inline]
__se_sys_copy_file_range fs/read_write.c:1644 [inline]
__arm64_sys_copy_file_range+0x308/0x5d4 fs/read_write.c:1644
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
-> #0 (&new->rf_sem){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237
lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
down_write+0x50/0xc0 kernel/locking/rwsem.c:1590
__ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
ocfs2_lock_refcount_tree+0x188/0x924 fs/ocfs2/refcounttree.c:463
ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3406 [inline]
ocfs2_refcount_cow+0x4a4/0xb6c fs/ocfs2/refcounttree.c:3467
ocfs2_cow_file_pos+0x2b4/0x314 fs/ocfs2/file.c:366
ocfs2_orphan_for_truncate fs/ocfs2/file.c:387 [inline]
ocfs2_truncate_file+0x354/0x12f4 fs/ocfs2/file.c:500
ocfs2_setattr+0x1148/0x17a0 fs/ocfs2/file.c:1212
notify_change+0x9a4/0xc50 fs/attr.c:552
do_truncate+0x198/0x210 fs/open.c:68
vfs_truncate+0x398/0x444 fs/open.c:118
do_sys_truncate+0xe4/0x1a8 fs/open.c:141
__do_sys_truncate fs/open.c:153 [inline]
__se_sys_truncate fs/open.c:151 [inline]
__arm64_sys_truncate+0x5c/0x74 fs/open.c:151
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
other info that might help us debug this:
Chain exists of:
&new->rf_sem --> &oi->ip_xattr_sem --> &ocfs2_file_ip_alloc_sem_key
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ocfs2_file_ip_alloc_sem_key);
lock(&oi->ip_xattr_sem);
lock(&ocfs2_file_ip_alloc_sem_key);
lock(&new->rf_sem);
*** DEADLOCK ***
3 locks held by syz.0.173/7608:
#0: ffff0000ff98e428 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:557
#1: ffff0000f67a2640 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:875 [inline]
#1: ffff0000f67a2640 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: do_truncate+0x164/0x210 fs/open.c:63
#2: ffff0000f67a22e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}, at: ocfs2_truncate_file+0x30c/0x12f4 fs/ocfs2/file.c:471
stack backtrace:
CPU: 0 UID: 0 PID: 7608 Comm: syz.0.173 Not tainted syzkaller #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Call trace:
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
__dump_stack+0x30/0x40 lib/dump_stack.c:94
dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
dump_stack+0x1c/0x28 lib/dump_stack.c:129
print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043
check_noncircular+0x154/0x174 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237
lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
down_write+0x50/0xc0 kernel/locking/rwsem.c:1590
__ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
ocfs2_lock_refcount_tree+0x188/0x924 fs/ocfs2/refcounttree.c:463
ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3406 [inline]
ocfs2_refcount_cow+0x4a4/0xb6c fs/ocfs2/refcounttree.c:3467
ocfs2_cow_file_pos+0x2b4/0x314 fs/ocfs2/file.c:366
ocfs2_orphan_for_truncate fs/ocfs2/file.c:387 [inline]
ocfs2_truncate_file+0x354/0x12f4 fs/ocfs2/file.c:500
ocfs2_setattr+0x1148/0x17a0 fs/ocfs2/file.c:1212
notify_change+0x9a4/0xc50 fs/attr.c:552
do_truncate+0x198/0x210 fs/open.c:68
vfs_truncate+0x398/0x444 fs/open.c:118
do_sys_truncate+0xe4/0x1a8 fs/open.c:141
__do_sys_truncate fs/open.c:153 [inline]
__se_sys_truncate fs/open.c:151 [inline]
__arm64_sys_truncate+0x5c/0x74 fs/open.c:151
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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