[syzbot] [ocfs2?] possible deadlock in ocfs2_xattr_ibody_find (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 848acc8ffe1b Merge tag 'fsverity-for-linus' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15786cc6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b7079b368dcec295
dashboard link: https://syzkaller.appspot.com/bug?extid=5d34d3019a843b1b211c
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/25bde0bfecb5/disk-848acc8f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8a5ebf809884/vmlinux-848acc8f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1d1810845ac3/bzImage-848acc8f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5d34d3...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.5.129/6534 is trying to acquire lock:
ffff8880539d2258 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}, at: ocfs2_xattr_ibody_find.constprop.0+0x381/0x4b0 fs/ocfs2/xattr.c:2731

but task is already holding lock:
ffff8880539d22e8 (&oi->ip_xattr_sem){++++}-{4:4}, at: ocfs2_xattr_set+0x429/0x2bb0 fs/ocfs2/xattr.c:3627

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&oi->ip_xattr_sem){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
ocfs2_init_acl+0x35b/0x840 fs/ocfs2/acl.c:367
ocfs2_mknod+0x173c/0x2770 fs/ocfs2/namei.c:414
ocfs2_create+0xf4/0x430 fs/ocfs2/namei.c:677
vfs_create+0x301/0x6c0 fs/namei.c:4202
filename_mknodat+0x2de/0x7f0 fs/namei.c:5185
__do_sys_mknodat fs/namei.c:5216 [inline]
__se_sys_mknodat fs/namei.c:5212 [inline]
__x64_sys_mknodat+0xb5/0xf0 fs/namei.c:5212
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&journal->j_trans_barrier){.+.+}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
ocfs2_start_trans+0x5cc/0x8f0 fs/ocfs2/journal.c:369
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:801 [inline]
ocfs2_reserve_suballoc_bits+0x49e/0x4b00 fs/ocfs2/suballoc.c:950
ocfs2_reserve_new_metadata_blocks+0x506/0xbe0 fs/ocfs2/suballoc.c:1100
ocfs2_expand_inline_dir.constprop.0+0xe21/0x3ff0 fs/ocfs2/dir.c:2873
ocfs2_extend_dir+0x1dc/0x1bf0 fs/ocfs2/dir.c:3235
ocfs2_prepare_dir_for_insert+0x130d/0x1770 fs/ocfs2/dir.c:4353
ocfs2_mknod+0x8c1/0x2770 fs/ocfs2/namei.c:298
ocfs2_create+0xf4/0x430 fs/ocfs2/namei.c:677
vfs_create+0x301/0x6c0 fs/namei.c:4202
filename_mknodat+0x2de/0x7f0 fs/namei.c:5185
__do_sys_mknodat fs/namei.c:5216 [inline]
__se_sys_mknodat fs/namei.c:5212 [inline]
__x64_sys_mknodat+0xb5/0xf0 fs/namei.c:5212
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (sb_internal#3){.+.+}-{0:0}:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
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/super.h:19 [inline]
sb_start_intwrite include/linux/fs/super.h:177 [inline]
ocfs2_start_trans+0x4bb/0x8f0 fs/ocfs2/journal.c:367
ocfs2_extend_dir+0x630/0x1bf0 fs/ocfs2/dir.c:3322
ocfs2_prepare_dx_dir_for_insert.isra.0+0x823/0xfb0 fs/ocfs2/dir.c:4273
ocfs2_prepare_dir_for_insert+0xf1c/0x1770 fs/ocfs2/dir.c:4329
ocfs2_mknod+0x8c1/0x2770 fs/ocfs2/namei.c:298
ocfs2_create+0xf4/0x430 fs/ocfs2/namei.c:677
vfs_create+0x301/0x6c0 fs/namei.c:4202
filename_mknodat+0x2de/0x7f0 fs/namei.c:5185
__do_sys_mknodat fs/namei.c:5216 [inline]
__se_sys_mknodat fs/namei.c:5212 [inline]
__x64_sys_mknodat+0xb5/0xf0 fs/namei.c:5212
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}:
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
ocfs2_xattr_ibody_find.constprop.0+0x381/0x4b0 fs/ocfs2/xattr.c:2731
ocfs2_xattr_set+0x441/0x2bb0 fs/ocfs2/xattr.c:3632
ocfs2_xattr_user_set+0xbd/0x100 fs/ocfs2/xattr.c:7430
__vfs_setxattr+0x175/0x1e0 fs/xattr.c:223
__vfs_setxattr_noperm+0x127/0x660 fs/xattr.c:257
__vfs_setxattr_locked+0x127/0x2b0 fs/xattr.c:318
vfs_setxattr+0x14a/0x390 fs/xattr.c:344
do_setxattr+0x145/0x180 fs/xattr.c:662
filename_setxattr+0x167/0x1d0 fs/xattr.c:690
path_setxattrat+0x1ff/0x3b0 fs/xattr.c:734
__do_sys_setxattr fs/xattr.c:768 [inline]
__se_sys_setxattr fs/xattr.c:764 [inline]
__x64_sys_setxattr+0xc6/0x140 fs/xattr.c:764
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

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);
rlock(&ocfs2_file_ip_alloc_sem_key);

*** DEADLOCK ***

3 locks held by syz.5.129/6534:
#0: ffff888035dd2450 (sb_writers#16){.+.+}-{0:0}, at: filename_setxattr+0xbf/0x1d0 fs/xattr.c:688
#1: ffff8880539d25a0 (&type->i_mutex_dir_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#1: ffff8880539d25a0 (&type->i_mutex_dir_key#10){+.+.}-{4:4}, at: vfs_setxattr+0x120/0x390 fs/xattr.c:343
#2: ffff8880539d22e8 (&oi->ip_xattr_sem){++++}-{4:4}, at: ocfs2_xattr_set+0x429/0x2bb0 fs/ocfs2/xattr.c:3627

stack backtrace:
CPU: 0 UID: 0 PID: 6534 Comm: syz.5.129 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
ocfs2_xattr_ibody_find.constprop.0+0x381/0x4b0 fs/ocfs2/xattr.c:2731
ocfs2_xattr_set+0x441/0x2bb0 fs/ocfs2/xattr.c:3632
ocfs2_xattr_user_set+0xbd/0x100 fs/ocfs2/xattr.c:7430
__vfs_setxattr+0x175/0x1e0 fs/xattr.c:223
__vfs_setxattr_noperm+0x127/0x660 fs/xattr.c:257
__vfs_setxattr_locked+0x127/0x2b0 fs/xattr.c:318
vfs_setxattr+0x14a/0x390 fs/xattr.c:344
do_setxattr+0x145/0x180 fs/xattr.c:662
filename_setxattr+0x167/0x1d0 fs/xattr.c:690
path_setxattrat+0x1ff/0x3b0 fs/xattr.c:734
__do_sys_setxattr fs/xattr.c:768 [inline]
__se_sys_setxattr fs/xattr.c:764 [inline]
__x64_sys_setxattr+0xc6/0x140 fs/xattr.c:764
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2bbd19e019
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:00007f2bbe057028 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f2bbd425fa0 RCX: 00007f2bbd19e019
RDX: 0000200000000200 RSI: 0000200000000100 RDI: 0000200000000000
RBP: 00007f2bbd23500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2bbd426038 R14: 00007f2bbd425fa0 R15: 00007fff84a2eb78
</TASK>


---
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