[v5.15] possible deadlock in chown_common

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8f790700c974 Linux 5.15.130
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=175f8798680000
kernel config: https://syzkaller.appspot.com/x/.config?x=ad91b773c8e4774d
dashboard link: https://syzkaller.appspot.com/bug?extid=097db46a03bf76e49ae4
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/aaadf9118183/disk-8f790700.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2a0be86c4355/vmlinux-8f790700.xz
kernel image: https://storage.googleapis.com/syzbot-assets/24850bb2ecc3/Image-8f790700.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+097db4...@syzkaller.appspotmail.com

REISERFS (device loop4): Using r5 hash to sort names
REISERFS (device loop4): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.130-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/8771 is trying to acquire lock:
ffff00010fdd8980 (&type->i_mutex_dir_key#8){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff00010fdd8980 (&type->i_mutex_dir_key#8){+.+.}-{3:3}, at: chown_common+0x3f8/0x74c fs/open.c:674

but task is already holding lock:
ffff000111cd4460 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#12){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1742 [inline]
sb_start_write+0xf0/0x3ac include/linux/fs.h:1812
mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421
reiserfs_ioctl+0x188/0x4b8 fs/reiserfs/ioctl.c:103
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (&sbi->lock){+.+.}-{3:3}:
__mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
reiserfs_lookup+0x130/0x3c4 fs/reiserfs/namei.c:364
__lookup_slow+0x250/0x388 fs/namei.c:1659
lookup_one_len+0x178/0x28c fs/namei.c:2688
reiserfs_lookup_privroot+0x8c/0x204 fs/reiserfs/xattr.c:980
reiserfs_fill_super+0x1494/0x1e8c fs/reiserfs/super.c:2196
mount_bdev+0x274/0x370 fs/super.c:1387
get_super_block+0x44/0x58 fs/reiserfs/super.c:2608
legacy_get_tree+0xd4/0x16c fs/fs_context.c:611
vfs_get_tree+0x90/0x274 fs/super.c:1517
do_new_mount+0x25c/0x8c4 fs/namespace.c:2994
path_mount+0x590/0x104c fs/namespace.c:3324
do_mount fs/namespace.c:3337 [inline]
__do_sys_mount fs/namespace.c:3545 [inline]
__se_sys_mount fs/namespace.c:3522 [inline]
__arm64_sys_mount+0x510/0x5e0 fs/namespace.c:3522
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&type->i_mutex_dir_key#8){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3787 [inline]
__lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
down_write+0x110/0x260 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]
chown_common+0x3f8/0x74c fs/open.c:674
vfs_fchown fs/open.c:748 [inline]
ksys_fchown+0xe0/0x158 fs/open.c:759
__do_sys_fchown fs/open.c:767 [inline]
__se_sys_fchown fs/open.c:765 [inline]
__arm64_sys_fchown+0x7c/0x94 fs/open.c:765
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
&type->i_mutex_dir_key#8 --> &sbi->lock --> sb_writers#12

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(sb_writers#12);
lock(&sbi->lock);
lock(sb_writers#12);
lock(&type->i_mutex_dir_key#8);

*** DEADLOCK ***

1 lock held by syz-executor.4/8771:
#0: ffff000111cd4460 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:421

stack backtrace:
CPU: 1 PID: 8771 Comm: syz-executor.4 Not tainted 5.15.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
check_noncircular+0x2cc/0x378 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 kernel/locking/lockdep.c:3787 [inline]
__lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
down_write+0x110/0x260 kernel/locking/rwsem.c:1541
inode_lock include/linux/fs.h:787 [inline]
chown_common+0x3f8/0x74c fs/open.c:674
vfs_fchown fs/open.c:748 [inline]
ksys_fchown+0xe0/0x158 fs/open.c:759
__do_sys_fchown fs/open.c:767 [inline]
__se_sys_fchown fs/open.c:765 [inline]
__arm64_sys_fchown+0x7c/0x94 fs/open.c:765
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584


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