[v5.15] possible deadlock in hid_hw_open (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: de8dfb3f0278 Linux 5.15.206
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16ab54c8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=c942bf8149406836b952
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3b00346a7a2/disk-de8dfb3f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cd8ff348788e/vmlinux-de8dfb3f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6d03a73b9540/bzImage-de8dfb3f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c942bf...@syzkaller.appspotmail.com

input: HID 0926:3333 as /devices/platform/dummy_hcd.1/usb2/2-1/2-1:0.0/0003:0926:3333.0004/input/input7
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/1:2/1113 is trying to acquire lock:
ffff88805a0c9ee0 (&hdev->ll_open_lock){+.+.}-{3:3}, at: hid_hw_open+0x23/0x160 drivers/hid/hid-core.c:2132

but task is already holding lock:
ffff888060f562c0 (&dev->mutex#2){+.+.}-{3:3}, at: input_open_device+0x4e/0x2e0 drivers/input/input.c:620

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&dev->mutex#2){+.+.}-{3:3}:
__mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
input_disconnect_device drivers/input/input.c:748 [inline]
__input_unregister_device+0x2e/0x320 drivers/input/input.c:2278
input_unregister_device+0x97/0xf0 drivers/input/input.c:2473
steam_client_ll_open+0x73/0x90 drivers/hid/hid-steam.c:640
hid_hw_open+0xdd/0x160 drivers/hid/hid-core.c:2137
hidraw_open+0x28f/0x8b0 drivers/hid/hidraw.c:289
chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414
do_dentry_open+0x7ff/0xf80 fs/open.c:826
do_open fs/namei.c:3616 [inline]
path_openat+0x26f5/0x2fa0 fs/namei.c:3750
do_filp_open+0x1e2/0x410 fs/namei.c:3777
do_sys_openat2+0x150/0x4b0 fs/open.c:1255
do_sys_open fs/open.c:1271 [inline]
__do_sys_openat fs/open.c:1287 [inline]
__se_sys_openat fs/open.c:1282 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1282
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&hdev->ll_open_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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_killable_nested+0x17/0x20 kernel/locking/mutex.c:758
hid_hw_open+0x23/0x160 drivers/hid/hid-core.c:2132
input_open_device+0x16c/0x2e0 drivers/input/input.c:640
kbd_connect+0xe9/0x130 drivers/tty/vt/keyboard.c:1581
input_attach_handler drivers/input/input.c:1046 [inline]
input_register_device+0xda7/0x1140 drivers/input/input.c:2429
hidinput_connect+0x2440/0x2d90 drivers/hid/hid-input.c:2046
hid_connect+0x46a/0xe10 drivers/hid/hid-core.c:1988
hid_hw_start+0x99/0x100 drivers/hid/hid-core.c:2095
hid_device_probe+0x2ea/0x360 drivers/hid/hid-core.c:2327
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a8/0x480 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
hid_add_device+0x389/0x530 drivers/hid/hid-core.c:2475
usbhid_probe+0xb92/0xf40 drivers/hid/usbhid/hid-core.c:1442
usb_probe_interface+0x5c5/0xb20 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a8/0x480 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
usb_set_configuration+0x1991/0x1fd0 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x139/0x270 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a8/0x480 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
usb_new_device+0xd65/0x1660 drivers/usb/core/hub.c:2632
hub_port_connect drivers/usb/core/hub.c:5497 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
port_event drivers/usb/core/hub.c:5799 [inline]
hub_event+0x2e4a/0x55e0 drivers/usb/core/hub.c:5881
process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&dev->mutex#2);
lock(&hdev->ll_open_lock);
lock(&dev->mutex#2);
lock(&hdev->ll_open_lock);

*** DEADLOCK ***

8 locks held by kworker/1:2/1113:
#0: ffff88801c044538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc90004b37d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88814800c220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
#2: ffff88814800c220 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x55e0 drivers/usb/core/hub.c:5827
#3: ffff88801f523220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
#3: ffff88801f523220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:954
#4: ffff888060e1a1a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
#4: ffff888060e1a1a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:954
#5: ffff88805a0c9ab0 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
#5: ffff88805a0c9ab0 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:954
#6: ffffffff8cf465e8 (input_mutex){+.+.}-{3:3}, at: input_register_device+0xb66/0x1140 drivers/input/input.c:2422
#7: ffff888060f562c0 (&dev->mutex#2){+.+.}-{3:3}, at: input_open_device+0x4e/0x2e0 drivers/input/input.c:620

stack backtrace:
CPU: 1 PID: 1113 Comm: kworker/1:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
check_noncircular+0x296/0x330 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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_killable_nested+0x17/0x20 kernel/locking/mutex.c:758
hid_hw_open+0x23/0x160 drivers/hid/hid-core.c:2132
input_open_device+0x16c/0x2e0 drivers/input/input.c:640
kbd_connect+0xe9/0x130 drivers/tty/vt/keyboard.c:1581
input_attach_handler drivers/input/input.c:1046 [inline]
input_register_device+0xda7/0x1140 drivers/input/input.c:2429
hidinput_connect+0x2440/0x2d90 drivers/hid/hid-input.c:2046
hid_connect+0x46a/0xe10 drivers/hid/hid-core.c:1988
hid_hw_start+0x99/0x100 drivers/hid/hid-core.c:2095
hid_device_probe+0x2ea/0x360 drivers/hid/hid-core.c:2327
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a8/0x480 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
hid_add_device+0x389/0x530 drivers/hid/hid-core.c:2475
usbhid_probe+0xb92/0xf40 drivers/hid/usbhid/hid-core.c:1442
usb_probe_interface+0x5c5/0xb20 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a8/0x480 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
usb_set_configuration+0x1991/0x1fd0 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x139/0x270 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a8/0x480 drivers/base/dd.c:979
bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
device_add+0xa00/0xfb0 drivers/base/core.c:3412
usb_new_device+0xd65/0x1660 drivers/usb/core/hub.c:2632
hub_port_connect drivers/usb/core/hub.c:5497 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5637 [inline]
port_event drivers/usb/core/hub.c:5799 [inline]
hub_event+0x2e4a/0x55e0 drivers/usb/core/hub.c:5881
process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
keytouch 0003:0926:3333.0004: input,hidraw0: USB HID v0.00 Keyboard [HID 0926:3333] on usb-dummy_hcd.1-1/input0
usb 2-1: USB disconnect, device number 3


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