[v6.6] possible deadlock in ocfs2_setattr

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syzbot

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Jun 20, 2025, 6:28:28 PM6/20/25
to syzkaller...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16ca530c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=989e7b73c470ae185e89
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+989e7b...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.6.94-syzkaller #0 Not tainted
------------------------------------------------------
syz.3.401/7622 is trying to acquire lock:
ffff88805c36a608 (sb_internal#2){.+.+}-{0:0}, at: ocfs2_setattr+0x95a/0x1b20 fs/ocfs2/file.c:1262

but task is already holding lock:
ffff888060c5a2e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_setattr+0x94b/0x1b20 fs/ocfs2/file.c:1261

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573
ocfs2_try_remove_refcount_tree+0xb7/0x320 fs/ocfs2/refcounttree.c:932
ocfs2_xattr_set+0x596/0x11f0 fs/ocfs2/xattr.c:3669
ocfs2_set_acl+0x4e1/0x590 fs/ocfs2/acl.c:254
ocfs2_iop_set_acl+0x1ab/0x2a0 fs/ocfs2/acl.c:286
set_posix_acl fs/posix_acl.c:956 [inline]
vfs_remove_acl+0x4e3/0x740 fs/posix_acl.c:1243
ovl_do_remove_acl fs/overlayfs/overlayfs.h:337 [inline]
ovl_workdir_create+0x409/0x760 fs/overlayfs/super.c:340
ovl_make_workdir fs/overlayfs/super.c:716 [inline]
ovl_get_workdir+0x300/0x1740 fs/overlayfs/super.c:874
ovl_fill_super+0x1345/0x3560 fs/overlayfs/super.c:1427
vfs_get_super fs/super.c:1346 [inline]
get_tree_nodev+0xb5/0x140 fs/super.c:1365
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3366
do_mount fs/namespace.c:3706 [inline]
__do_sys_mount fs/namespace.c:3915 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3892
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #3 (&oi->ip_xattr_sem){++++}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
ocfs2_init_acl+0x2fa/0x720 fs/ocfs2/acl.c:366
ocfs2_mknod+0x12e5/0x20f0 fs/ocfs2/namei.c:410
ocfs2_create+0x196/0x410 fs/ocfs2/namei.c:674
lookup_open fs/namei.c:3488 [inline]
open_last_lookups fs/namei.c:3556 [inline]
path_openat+0x1277/0x3190 fs/namei.c:3786
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
do_sys_open fs/open.c:1434 [inline]
__do_sys_openat fs/open.c:1450 [inline]
__se_sys_openat fs/open.c:1445 [inline]
__x64_sys_openat+0x139/0x160 fs/open.c:1445
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (jbd2_handle){++++}-{0:0}:
start_this_handle+0x1e9d/0x20c0 fs/jbd2/transaction.c:448
jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505
jbd2_journal_start+0x2a/0x40 fs/jbd2/transaction.c:544
ocfs2_start_trans+0x376/0x6c0 fs/ocfs2/journal.c:374
ocfs2_mknod+0xe47/0x20f0 fs/ocfs2/namei.c:361
ocfs2_create+0x196/0x410 fs/ocfs2/namei.c:674
lookup_open fs/namei.c:3488 [inline]
open_last_lookups fs/namei.c:3556 [inline]
path_openat+0x1277/0x3190 fs/namei.c:3786
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
do_sys_open fs/open.c:1434 [inline]
__do_sys_open fs/open.c:1442 [inline]
__se_sys_open fs/open.c:1438 [inline]
__x64_sys_open+0x11f/0x140 fs/open.c:1438
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&journal->j_trans_barrier){.+.+}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
ocfs2_start_trans+0x36a/0x6c0 fs/ocfs2/journal.c:372
ocfs2_mknod+0xe47/0x20f0 fs/ocfs2/namei.c:361
ocfs2_create+0x196/0x410 fs/ocfs2/namei.c:674
lookup_open fs/namei.c:3488 [inline]
open_last_lookups fs/namei.c:3556 [inline]
path_openat+0x1277/0x3190 fs/namei.c:3786
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
do_sys_open fs/open.c:1434 [inline]
__do_sys_open fs/open.c:1442 [inline]
__se_sys_open fs/open.c:1438 [inline]
__x64_sys_open+0x11f/0x140 fs/open.c:1438
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (sb_internal#2){.+.+}-{0:0}:
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+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1633 [inline]
sb_start_intwrite include/linux/fs.h:1755 [inline]
ocfs2_start_trans+0x26b/0x6c0 fs/ocfs2/journal.c:370
ocfs2_setattr+0x95a/0x1b20 fs/ocfs2/file.c:1262
notify_change+0xb0d/0xe10 fs/attr.c:499
ovl_do_notify_change fs/overlayfs/overlayfs.h:188 [inline]
ovl_workdir_create+0x5de/0x760 fs/overlayfs/super.c:350
ovl_make_workdir fs/overlayfs/super.c:716 [inline]
ovl_get_workdir+0x300/0x1740 fs/overlayfs/super.c:874
ovl_fill_super+0x1345/0x3560 fs/overlayfs/super.c:1427
vfs_get_super fs/super.c:1346 [inline]
get_tree_nodev+0xb5/0x140 fs/super.c:1365
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3366
do_mount fs/namespace.c:3706 [inline]
__do_sys_mount fs/namespace.c:3915 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3892
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
sb_internal#2 --> &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);
rlock(sb_internal#2);

*** DEADLOCK ***

5 locks held by syz.3.401/7622:
#0: ffff88806b4760e0 (&type->s_umount_key#57/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x920 fs/super.c:352
#1: ffff88805c36a418 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:403
#2: ffff888060fd2658 (&sb->s_type->i_mutex_key#24/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline]
#2: ffff888060fd2658 (&sb->s_type->i_mutex_key#24/1){+.+.}-{3:3}, at: ovl_workdir_create+0x150/0x760 fs/overlayfs/super.c:290
#3: ffff888060c5a658 (&sb->s_type->i_mutex_key#24){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#3: ffff888060c5a658 (&sb->s_type->i_mutex_key#24){+.+.}-{3:3}, at: ovl_workdir_create+0x557/0x760 fs/overlayfs/super.c:349
#4: ffff888060c5a2e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_setattr+0x94b/0x1b20 fs/ocfs2/file.c:1261

stack backtrace:
CPU: 0 PID: 7622 Comm: syz.3.401 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
check_noncircular+0x2bd/0x3c0 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+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1633 [inline]
sb_start_intwrite include/linux/fs.h:1755 [inline]
ocfs2_start_trans+0x26b/0x6c0 fs/ocfs2/journal.c:370
ocfs2_setattr+0x95a/0x1b20 fs/ocfs2/file.c:1262
notify_change+0xb0d/0xe10 fs/attr.c:499
ovl_do_notify_change fs/overlayfs/overlayfs.h:188 [inline]
ovl_workdir_create+0x5de/0x760 fs/overlayfs/super.c:350
ovl_make_workdir fs/overlayfs/super.c:716 [inline]
ovl_get_workdir+0x300/0x1740 fs/overlayfs/super.c:874
ovl_fill_super+0x1345/0x3560 fs/overlayfs/super.c:1427
vfs_get_super fs/super.c:1346 [inline]
get_tree_nodev+0xb5/0x140 fs/super.c:1365
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3366
do_mount fs/namespace.c:3706 [inline]
__do_sys_mount fs/namespace.c:3915 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3892
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f64ad38e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f64ae1c1038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f64ad5b6240 RCX: 00007f64ad38e929
RDX: 0000200000000080 RSI: 00002000000000c0 RDI: 0000000000000000
RBP: 00007f64ad410b39 R08: 0000200000000a00 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f64ad5b6240 R15: 00007ffeef025738
</TASK>
overlayfs: upper fs does not support tmpfile.
overlayfs: upper fs does not support RENAME_WHITEOUT.
overlayfs: failed to set xattr on upper
overlayfs: ...falling back to redirect_dir=nofollow.
overlayfs: ...falling back to index=off.
overlayfs: ...falling back to uuid=null.
overlayfs: upper fs missing required features.


---
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup

syzbot

unread,
Jun 23, 2025, 4:27:35 PM6/23/25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1108e182580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=989e7b73c470ae185e89
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17166dd4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1715bb0c580000
mounted in repro: https://storage.googleapis.com/syzbot-assets/bfb577d30a9d/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=107aeb0c580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+989e7b...@syzkaller.appspotmail.com

option from the mount to silence this warning.
=======================================================
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
6.6.94-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor331/5773 is trying to acquire lock:
ffff88802e9b2608 (sb_internal#2){.+.+}-{0:0}, at: ocfs2_setattr+0x95a/0x1b20 fs/ocfs2/file.c:1262

but task is already holding lock:
ffff888076dd4da0 (&oi->ip_alloc_sem){+.+.}-{3:3}, at: ocfs2_setattr+0x94b/0x1b20 fs/ocfs2/file.c:1261

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&oi->ip_alloc_sem){+.+.}-{3:3}:
ocfs2_mkdir+0x196/0x410 fs/ocfs2/namei.c:657
vfs_mkdir+0x296/0x440 fs/namei.c:4113
do_mkdirat+0x1d4/0x440 fs/namei.c:4136
__do_sys_mkdirat fs/namei.c:4151 [inline]
__se_sys_mkdirat fs/namei.c:4149 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4149
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (jbd2_handle){.+.+}-{0:0}:
start_this_handle+0x1e9d/0x20c0 fs/jbd2/transaction.c:448
jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505
jbd2_journal_start+0x2a/0x40 fs/jbd2/transaction.c:544
ocfs2_start_trans+0x376/0x6c0 fs/ocfs2/journal.c:374
ocfs2_mknod+0xe47/0x20f0 fs/ocfs2/namei.c:361
ocfs2_mkdir+0x196/0x410 fs/ocfs2/namei.c:657
vfs_mkdir+0x296/0x440 fs/namei.c:4113
do_mkdirat+0x1d4/0x440 fs/namei.c:4136
__do_sys_mkdirat fs/namei.c:4151 [inline]
__se_sys_mkdirat fs/namei.c:4149 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4149
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&journal->j_trans_barrier){.+.+}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
ocfs2_start_trans+0x36a/0x6c0 fs/ocfs2/journal.c:372
ocfs2_mknod+0xe47/0x20f0 fs/ocfs2/namei.c:361
ocfs2_mkdir+0x196/0x410 fs/ocfs2/namei.c:657
vfs_mkdir+0x296/0x440 fs/namei.c:4113
do_mkdirat+0x1d4/0x440 fs/namei.c:4136
__do_sys_mkdirat fs/namei.c:4151 [inline]
__se_sys_mkdirat fs/namei.c:4149 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4149
sb_internal#2 --> &oi->ip_xattr_sem --> &oi->ip_alloc_sem

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&oi->ip_alloc_sem);
lock(&oi->ip_xattr_sem);
lock(&oi->ip_alloc_sem);
rlock(sb_internal#2);

*** DEADLOCK ***

5 locks held by syz-executor331/5773:
#0: ffff88802fe400e0 (&type->s_umount_key#46/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x920 fs/super.c:352
#1: ffff88802e9b2418 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:403
#2: ffff888076dd3498 (&sb->s_type->i_mutex_key#15/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:839 [inline]
#2: ffff888076dd3498 (&sb->s_type->i_mutex_key#15/1){+.+.}-{3:3}, at: ovl_workdir_create+0x150/0x760 fs/overlayfs/super.c:290
#3: ffff888076dd5118 (&sb->s_type->i_mutex_key#17){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#3: ffff888076dd5118 (&sb->s_type->i_mutex_key#17){+.+.}-{3:3}, at: ovl_workdir_create+0x557/0x760 fs/overlayfs/super.c:349
#4: ffff888076dd4da0 (&oi->ip_alloc_sem){+.+.}-{3:3}, at: ocfs2_setattr+0x94b/0x1b20 fs/ocfs2/file.c:1261

stack backtrace:
CPU: 0 PID: 5773 Comm: syz-executor331 Not tainted 6.6.94-syzkaller #0
RIP: 0033:0x7f28c95367b9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc5663d548 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f28c95367b9
RDX: 0000200000000340 RSI: 00002000000000c0 RDI: 0000000000000000
RBP: 00007f28c95ad610 R08: 00002000000002c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc5663d718 R14: 0000000000000001 R15: 0000000000000001
</TASK>


---
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