syzbot

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.42/4547 is trying to acquire lock:
ffff8880302b6070 (&newdev->mutex){+.+.}-{3:3}, at: uinput_request_send drivers/input/misc/uinput.c:150 [inline]
ffff8880302b6070 (&newdev->mutex){+.+.}-{3:3}, at: uinput_request_submit+0x198/0x700 drivers/input/misc/uinput.c:181

but task is already holding lock:
ffff8880294768b0 (&ff->mutex){+.+.}-{3:3}, at: input_ff_upload+0x397/0x9c0 drivers/input/ff-core.c:122

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&ff->mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       input_ff_flush+0x5a/0x130 drivers/input/ff-core.c:242
       input_flush_device+0x97/0xc0 drivers/input/input.c:682
       evdev_release+0xe0/0x800 drivers/input/evdev.c:444
       __fput+0x22c/0x920 fs/file_table.c:320
       task_work_run+0x1ca/0x250 kernel/task_work.c:203
       resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
       exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
       __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (
&dev->mutex#2
){+.+.}-{3:3}
:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       input_register_handle+0x67/0x3a0 drivers/input/input.c:2629
       kbd_connect+0xbf/0x130 drivers/tty/vt/keyboard.c:1589
       input_attach_handler drivers/input/input.c:1060 [inline]
       input_register_device+0xdfd/0x1310 drivers/input/input.c:2470
       acpi_button_add+0x6b7/0xae0 drivers/acpi/button.c:570
       acpi_device_probe+0xa3/0x300 drivers/acpi/bus.c:1023
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x2aa/0xc70 drivers/base/dd.c:639
       __driver_probe_device+0x18c/0x330 drivers/base/dd.c:785
       driver_probe_device+0x4f/0x420 drivers/base/dd.c:815
       __driver_attach+0x44a/0x6e0 drivers/base/dd.c:1201
       bus_for_each_dev+0x175/0x1e0 drivers/base/bus.c:303
       bus_add_driver+0x30a/0x5a0 drivers/base/bus.c:620
       driver_register+0x32d/0x430 drivers/base/driver.c:246
       do_one_initcall+0x214/0x7a0 init/main.c:1298
       do_initcall_level+0x137/0x1e4 init/main.c:1371
       do_initcalls+0x4b/0x8a init/main.c:1387
       kernel_init_freeable+0x3fa/0x5ac init/main.c:1626
       kernel_init+0x19/0x1b0 init/main.c:1514
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #1 (
input_mutex){+.+.}-{3:3}
:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       input_register_device+0xbc6/0x1310 drivers/input/input.c:2463
       uinput_create_device+0x422/0x670 drivers/input/misc/uinput.c:364
       uinput_ioctl_handler+0x7d8/0x14c0 drivers/input/misc/uinput.c:884
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (
&newdev->mutex
){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       uinput_request_send drivers/input/misc/uinput.c:150 [inline]
       uinput_request_submit+0x198/0x700 drivers/input/misc/uinput.c:181
       uinput_dev_upload_effect+0x14d/0x1d0 drivers/input/misc/uinput.c:256
       input_ff_upload+0x587/0x9c0 drivers/input/ff-core.c:152
       evdev_do_ioctl drivers/input/evdev.c:1183 [inline]
       evdev_ioctl_handler+0x16f7/0x1de0 drivers/input/evdev.c:1272
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  
&newdev->mutex --> 
&dev->mutex#2
 --> &ff->mutex


 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ff->mutex
);
                               lock(
&dev->mutex#2
);
                               lock(
&ff->mutex);
  lock(&newdev->mutex
);

 *** DEADLOCK ***

2 locks held by syz.1.42/4547:
 #0: ffff888056a50110
 (&evdev->mutex
){+.+.}-{3:3}
, at: evdev_ioctl_handler+0x122/0x1de0 drivers/input/evdev.c:1263
 #1: ffff8880294768b0
 (&ff->mutex
){+.+.}-{3:3}, at: input_ff_upload+0x397/0x9c0 drivers/input/ff-core.c:122

stack backtrace:
CPU: 1 PID: 4547 Comm: syz.1.42 Tainted: G      D            syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 uinput_request_send drivers/input/misc/uinput.c:150 [inline]
 uinput_request_submit+0x198/0x700 drivers/input/misc/uinput.c:181
 uinput_dev_upload_effect+0x14d/0x1d0 drivers/input/misc/uinput.c:256
 input_ff_upload+0x587/0x9c0 drivers/input/ff-core.c:152
 evdev_do_ioctl drivers/input/evdev.c:1183 [inline]
 evdev_ioctl_handler+0x16f7/0x1de0 drivers/input/evdev.c:1272
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f353cb8eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc815affe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f353cde5fa0 RCX: 00007f353cb8eec9
RDX: 0000200000000300 RSI: 0000000040304580 RDI: 0000000000000003
RBP: 00007f353cc11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f353cde5fa0 R14: 00007f353cde5fa0 R15: 0000000000000003
 </TASK>