[v5.15] possible deadlock in filename_create (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9465fef4ae35 Linux 5.15.153
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14132bfd180000
kernel config: https://syzkaller.appspot.com/x/.config?x=74ff83133fa97f6c
dashboard link: https://syzkaller.appspot.com/bug?extid=b6f2fe752b6507098b78
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/3c82fda40b43/disk-9465fef4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ec13893dc103/vmlinux-9465fef4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7b44910e5283/Image-9465fef4.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6f2fe...@syzkaller.appspotmail.com

REISERFS warning (device loop1): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)
REISERFS (device loop1): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.153-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/9932 is trying to acquire lock:
ffff0000e9409d60 (&type->i_mutex_dir_key#9/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:824 [inline]
ffff0000e9409d60 (&type->i_mutex_dir_key#9/1){+.+.}-{3:3}, at: filename_create+0x204/0x468 fs/namei.c:3835

but task is already holding lock:
ffff0000d998c460 (sb_writers#22){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#22){.+.+}-{0:0}
:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1787 [inline]
sb_start_write+0xf0/0x3ac include/linux/fs.h:1857
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: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 (&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_one_qstr_excl+0x108/0x230 fs/namei.c:1563
filename_create+0x230/0x468 fs/namei.c:3836
do_mkdirat+0xac/0x610 fs/namei.c:4080
__do_sys_mkdirat fs/namei.c:4105 [inline]
__se_sys_mkdirat fs/namei.c:4103 [inline]
__arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4103
__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#9/1){+.+.}-{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_nested+0x118/0x26c kernel/locking/rwsem.c:1657
inode_lock_nested include/linux/fs.h:824 [inline]
filename_create+0x204/0x468 fs/namei.c:3835
do_mkdirat+0xac/0x610 fs/namei.c:4080
__do_sys_mkdirat fs/namei.c:4105 [inline]
__se_sys_mkdirat fs/namei.c:4103 [inline]
__arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4103
__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#9/1 --> &sbi->lock --> sb_writers#22

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(sb_writers#22);
lock(&sbi->lock);
lock(sb_writers#22);
lock(&type->i_mutex_dir_key#9/1);

*** DEADLOCK ***

1 lock held by syz-executor.1/9932:
#0: ffff0000d998c460 (sb_writers#22){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377

stack backtrace:
CPU: 1 PID: 9932 Comm: syz-executor.1 Not tainted 5.15.153-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_nested+0x118/0x26c kernel/locking/rwsem.c:1657
inode_lock_nested include/linux/fs.h:824 [inline]
filename_create+0x204/0x468 fs/namei.c:3835
do_mkdirat+0xac/0x610 fs/namei.c:4080
__do_sys_mkdirat fs/namei.c:4105 [inline]
__se_sys_mkdirat fs/namei.c:4103 [inline]
__arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4103
__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
REISERFS warning (device loop1): vs-13060 reiserfs_update_sd_size: stat data of object [1 2 0x0 SD] (nlink == 1) not found (pos 2)


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 9465fef4ae35 Linux 5.15.153
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1717a6e5180000

kernel config: https://syzkaller.appspot.com/x/.config?x=74ff83133fa97f6c
dashboard link: https://syzkaller.appspot.com/bug?extid=b6f2fe752b6507098b78
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10268b21180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=163ecb76180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3c82fda40b43/disk-9465fef4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ec13893dc103/vmlinux-9465fef4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7b44910e5283/Image-9465fef4.gz.xz

mounted in repro #1: https://storage.googleapis.com/syzbot-assets/74caf539e86b/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/84e93288a2dc/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6f2fe...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.15.153-syzkaller #0 Not tainted
------------------------------------------------------

syz-executor103/3998 is trying to acquire lock:
ffff0000cad3a090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27

but task is already holding lock:

ffff0000de8fb140 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:824 [inline]
ffff0000de8fb140 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x204/0x468 fs/namei.c:3835

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}:

down_write_nested+0x118/0x26c kernel/locking/rwsem.c:1657
inode_lock_nested include/linux/fs.h:824 [inline]
filename_create+0x204/0x468 fs/namei.c:3835
do_mkdirat+0xac/0x610 fs/namei.c:4080
__do_sys_mkdirat fs/namei.c:4105 [inline]
__se_sys_mkdirat fs/namei.c:4103 [inline]
__arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4103
__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 (sb_writers#8){.+.+}-{0:0}:

percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1787 [inline]
sb_start_write+0xf0/0x3ac include/linux/fs.h:1857
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: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 (&sbi->lock){+.+.}-{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

__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_one_qstr_excl+0x108/0x230 fs/namei.c:1563
filename_create+0x230/0x468 fs/namei.c:3836
do_mkdirat+0xac/0x610 fs/namei.c:4080
__do_sys_mkdirat fs/namei.c:4105 [inline]
__se_sys_mkdirat fs/namei.c:4103 [inline]
__arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4103
__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:

&sbi->lock --> sb_writers#8 --> &type->i_mutex_dir_key#6/1

Possible unsafe locking scenario:

CPU0 CPU1
---- ----

lock(&type->i_mutex_dir_key#6/1);
lock(sb_writers#8);
lock(&type->i_mutex_dir_key#6/1);
lock(&sbi->lock);

*** DEADLOCK ***

2 locks held by syz-executor103/3998:
#0: ffff0000cfd46460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
#1: ffff0000de8fb140 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:824 [inline]
#1: ffff0000de8fb140 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x204/0x468 fs/namei.c:3835

stack backtrace:
CPU: 0 PID: 3998 Comm: syz-executor103 Not tainted 5.15.153-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

__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_one_qstr_excl+0x108/0x230 fs/namei.c:1563
filename_create+0x230/0x468 fs/namei.c:3836
do_mkdirat+0xac/0x610 fs/namei.c:4080
__do_sys_mkdirat fs/namei.c:4105 [inline]
__se_sys_mkdirat fs/namei.c:4103 [inline]
__arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4103
__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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