[v5.15] possible deadlock in vfs_rename

[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=139bb05c980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ab74f93e8454887c
dashboard link: https://syzkaller.appspot.com/bug?extid=65cd0f5b5b0193be0bf2
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/0accc7dacf9d/disk-284087d4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fb6b5b110f8c/vmlinux-284087d4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6763bebdbfea/Image-284087d4.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+65cd0f...@syzkaller.appspotmail.com

REISERFS (device loop3): using 3.5.x disk format
REISERFS (device loop3): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.158-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/8285 is trying to acquire lock:
ffff0000def6d900 (&type->i_mutex_dir_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
ffff0000def6d900 (&type->i_mutex_dir_key#12){+.+.}-{3:3}, at: vfs_rename+0x68c/0xe04 fs/namei.c:4797

but task is already holding lock:
ffff0000def6e640 (&type->i_mutex_dir_key#12/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:824 [inline]
ffff0000def6e640 (&type->i_mutex_dir_key#12/2){+.+.}-{3:3}, at: vfs_rename+0x624/0xe04 fs/namei.c:4795

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&type->i_mutex_dir_key#12/2){+.+.}-{3:3}:
down_write_nested+0xc0/0x130 kernel/locking/rwsem.c:1667
inode_lock_nested include/linux/fs.h:824 [inline]
xattr_rmdir fs/reiserfs/xattr.c:106 [inline]
delete_one_xattr+0xe8/0x2c8 fs/reiserfs/xattr.c:338
reiserfs_for_each_xattr+0x794/0x8d8 fs/reiserfs/xattr.c:311
reiserfs_delete_xattrs+0x2c/0xa4 fs/reiserfs/xattr.c:364
reiserfs_evict_inode+0x1dc/0x3f0 fs/reiserfs/inode.c:53
evict+0x260/0x68c fs/inode.c:587
iput_final fs/inode.c:1705 [inline]
iput+0x744/0x824 fs/inode.c:1731
d_delete_notify include/linux/fsnotify.h:261 [inline]
vfs_rmdir+0x2f8/0x3f0 fs/namei.c:4162
do_rmdir+0x2e8/0x84c fs/namei.c:4210
__do_sys_unlinkat fs/namei.c:4390 [inline]
__se_sys_unlinkat fs/namei.c:4384 [inline]
__arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4384
__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:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (&type->i_mutex_dir_key#12/3){+.+.}-{3:3}:
down_write_nested+0xc0/0x130 kernel/locking/rwsem.c:1667
inode_lock_nested include/linux/fs.h:824 [inline]
open_xa_root fs/reiserfs/xattr.c:127 [inline]
open_xa_dir+0x11c/0x578 fs/reiserfs/xattr.c:152
xattr_lookup+0x3c/0x268 fs/reiserfs/xattr.c:395
reiserfs_xattr_set_handle+0xe4/0xc10 fs/reiserfs/xattr.c:540
reiserfs_xattr_set+0x398/0x4b0 fs/reiserfs/xattr.c:640
trusted_set+0x98/0xec fs/reiserfs/xattr_trusted.c:31
__vfs_setxattr+0x388/0x3a4 fs/xattr.c:182
__vfs_setxattr_noperm+0x110/0x528 fs/xattr.c:216
__vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:277
vfs_setxattr+0x1a8/0x344 fs/xattr.c:303
do_setxattr fs/xattr.c:588 [inline]
setxattr+0x250/0x2b4 fs/xattr.c:611
path_setxattr+0x17c/0x258 fs/xattr.c:630
__do_sys_lsetxattr fs/xattr.c:653 [inline]
__se_sys_lsetxattr fs/xattr.c:649 [inline]
__arm64_sys_lsetxattr+0xbc/0xd8 fs/xattr.c:649
__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:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&type->i_mutex_dir_key#12){+.+.}-{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:3788 [inline]
__lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
down_write+0xbc/0x12c kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:789 [inline]
vfs_rename+0x68c/0xe04 fs/namei.c:4797
do_renameat2+0xa00/0x10c0 fs/namei.c:4985
__do_sys_renameat2 fs/namei.c:5018 [inline]
__se_sys_renameat2 fs/namei.c:5015 [inline]
__arm64_sys_renameat2+0xe0/0xfc fs/namei.c:5015
__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:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
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#12 --> &type->i_mutex_dir_key#12/3 --> &type->i_mutex_dir_key#12/2

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&type->i_mutex_dir_key#12/2);
lock(&type->i_mutex_dir_key#12/3);
lock(&type->i_mutex_dir_key#12/2);
lock(&type->i_mutex_dir_key#12);

*** DEADLOCK ***

5 locks held by syz-executor.3/8285:
#0: ffff0000e2e30460 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
#1: ffff0000e2e30748 (&type->s_vfs_rename_key#5){+.+.}-{3:3}, at: lock_rename fs/namei.c:3016 [inline]
#1: ffff0000e2e30748 (&type->s_vfs_rename_key#5){+.+.}-{3:3}, at: do_renameat2+0x494/0x10c0 fs/namei.c:4924
#2: ffff0000def6b140 (&type->i_mutex_dir_key#12/1){+.+.}-{3:3}, at: lock_rename fs/namei.c:3017 [inline]
#2: ffff0000def6b140 (&type->i_mutex_dir_key#12/1){+.+.}-{3:3}, at: do_renameat2+0x508/0x10c0 fs/namei.c:4924
#3: ffff0000def6dfa0 (&type->i_mutex_dir_key#12/5){+.+.}-{3:3}, at: do_renameat2+0x534/0x10c0 fs/namei.c:4924
#4: ffff0000def6e640 (&type->i_mutex_dir_key#12/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:824 [inline]
#4: ffff0000def6e640 (&type->i_mutex_dir_key#12/2){+.+.}-{3:3}, at: vfs_rename+0x624/0xe04 fs/namei.c:4795

stack backtrace:
CPU: 1 PID: 8285 Comm: syz-executor.3 Not tainted 5.15.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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:3788 [inline]
__lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
down_write+0xbc/0x12c kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:789 [inline]
vfs_rename+0x68c/0xe04 fs/namei.c:4797
do_renameat2+0xa00/0x10c0 fs/namei.c:4985
__do_sys_renameat2 fs/namei.c:5018 [inline]
__se_sys_renameat2 fs/namei.c:5015 [inline]
__arm64_sys_renameat2+0xe0/0xfc fs/namei.c:5015
__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:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584


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