[v5.15] possible deadlock in vfs_utimes

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 284087d4f7d5 Linux 5.15.158
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11ad04e0980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b0dd54e4b5171ebc
dashboard link: https://syzkaller.appspot.com/bug?extid=981d76eeab268603b6f1
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c2e33c1db6bf/disk-284087d4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d9f77284af1d/vmlinux-284087d4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a600323dd149/bzImage-284087d4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+981d76...@syzkaller.appspotmail.com

REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.158-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/5876 is trying to acquire lock:
ffff88805ebe02e0 (&type->i_mutex_dir_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
ffff88805ebe02e0 (&type->i_mutex_dir_key#14){+.+.}-{3:3}, at: vfs_utimes+0x449/0x760 fs/utimes.c:64

but task is already holding lock:
ffff88807bab2460 (sb_writers#21){.+.+}-{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#21){.+.+}-{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:1811 [inline]
sb_start_write+0x4f/0x1c0 include/linux/fs.h:1881
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+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #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+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&type->i_mutex_dir_key#14){+.+.}-{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+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:789 [inline]
vfs_utimes+0x449/0x760 fs/utimes.c:64
do_utimes_fd fs/utimes.c:119 [inline]
do_utimes+0x15e/0x270 fs/utimes.c:143
__do_sys_utimensat fs/utimes.c:163 [inline]
__se_sys_utimensat fs/utimes.c:147 [inline]
__x64_sys_utimensat+0x14b/0x250 fs/utimes.c:147
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
&type->i_mutex_dir_key#14 --> &sbi->lock --> sb_writers#21

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(sb_writers#21);
lock(&sbi->lock);
lock(sb_writers#21);
lock(&type->i_mutex_dir_key#14);

*** DEADLOCK ***

1 lock held by syz-executor.2/5876:
#0: ffff88807bab2460 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:377

stack backtrace:
CPU: 0 PID: 5876 Comm: syz-executor.2 Not tainted 5.15.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 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+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:789 [inline]
vfs_utimes+0x449/0x760 fs/utimes.c:64
do_utimes_fd fs/utimes.c:119 [inline]
do_utimes+0x15e/0x270 fs/utimes.c:143
__do_sys_utimensat fs/utimes.c:163 [inline]
__se_sys_utimensat fs/utimes.c:147 [inline]
__x64_sys_utimensat+0x14b/0x250 fs/utimes.c:147
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7fdd590d69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7fdbb030c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000118
RAX: ffffffffffffffda RBX: 00007f7fdd6bef80 RCX: 00007f7fdd590d69
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f7fdd5dd49e R08: 0000000000000000 R09: 0000000000000000
R10: 0500000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f7fdd6bef80 R15: 00007ffd4fce0d58
</TASK>


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