[v5.15] possible deadlock in vfs_setxattr

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 458ce51d0356 Linux 5.15.149
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1330f106180000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c016b4e71f1c777
dashboard link: https://syzkaller.appspot.com/bug?extid=c1b05565be0ff9a5d30f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17d7fd4a180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139ed254180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c84f9ea3bbab/disk-458ce51d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70bdbf46c57d/vmlinux-458ce51d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/73fc8d1364f3/bzImage-458ce51d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/c4bb424a8f3d/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c1b055...@syzkaller.appspotmail.com

REISERFS (device loop0): journal params: device loop0, size 512, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.149-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor119/3500 is trying to acquire lock:
ffff8880736882e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff8880736882e0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}, at: vfs_setxattr+0x1dd/0x420 fs/xattr.c:302

but task is already holding lock:
ffff88801598e460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#9){.+.+}-{0:0}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1785 [inline]
sb_start_write+0x4f/0x1c0 include/linux/fs.h:1855
mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:421
reiserfs_ioctl+0x170/0x340 fs/reiserfs/ioctl.c:103
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #1 (&sbi->lock){+.+.}-{3:3}:
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
reiserfs_write_lock+0x76/0xd0 fs/reiserfs/lock.c:27
reiserfs_lookup+0x15c/0x4b0 fs/reiserfs/namei.c:364
__lookup_slow+0x275/0x3d0 fs/namei.c:1663
lookup_one_len+0x187/0x2d0 fs/namei.c:2718
reiserfs_lookup_privroot+0x85/0x1e0 fs/reiserfs/xattr.c:980
reiserfs_fill_super+0x2224/0x2690 fs/reiserfs/super.c:2178
mount_bdev+0x2c9/0x3f0 fs/super.c:1387
legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
vfs_get_tree+0x88/0x270 fs/super.c:1517
do_new_mount+0x2ba/0xb40 fs/namespace.c:3005
do_mount fs/namespace.c:3348 [inline]
__do_sys_mount fs/namespace.c:3556 [inline]
__se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3533
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (&type->i_mutex_dir_key#6){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
down_write+0x97/0x170 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]
vfs_setxattr+0x1dd/0x420 fs/xattr.c:302
do_setxattr fs/xattr.c:588 [inline]
setxattr+0x27e/0x2e0 fs/xattr.c:611
path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
__do_sys_setxattr fs/xattr.c:646 [inline]
__se_sys_setxattr fs/xattr.c:642 [inline]
__x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb

other info that might help us debug this:

Chain exists of:
&type->i_mutex_dir_key#6 --> &sbi->lock --> sb_writers#9

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(sb_writers#9);
lock(&sbi->lock);
lock(sb_writers#9);
lock(&type->i_mutex_dir_key#6);

*** DEADLOCK ***

1 lock held by syz-executor119/3500:
#0: ffff88801598e460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377

stack backtrace:
CPU: 0 PID: 3500 Comm: syz-executor119 Not tainted 5.15.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
down_write+0x97/0x170 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]
vfs_setxattr+0x1dd/0x420 fs/xattr.c:302
do_setxattr fs/xattr.c:588 [inline]
setxattr+0x27e/0x2e0 fs/xattr.c:611
path_setxattr+0x1bc/0x2a0 fs/xattr.c:630
__do_sys_setxattr fs/xattr.c:646 [inline]
__se_sys_setxattr fs/xattr.c:642 [inline]
__x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f5dffa2e649
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:00007ffec44b1498 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007ffec44b1668 RCX: 00007f5dffa2e649
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000020000080
RBP: 00007f5dffaa2610 R08: 0000000000000001 R09: 00007ffec44b1668


---
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 syzk...@googlegroups.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 syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

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