======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
udevd/5810 is trying to acquire lock:
ffff88802779f0b0 (&ff->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
ffff88802779f0b0 (&ff->mutex){+.+.}-{4:4}, at: input_ff_flush+0x63/0x1b0 drivers/input/ff-core.c:231

but task is already holding lock:
ffff88802621e2c0 (&dev->mutex#2){+.+.}-{4:4}, at: class_mutex_intr_constructor include/linux/mutex.h:255 [inline]
ffff88802621e2c0 (&dev->mutex#2){+.+.}-{4:4}, at: input_flush_device+0x4a/0x140 drivers/input/input.c:626

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&dev->mutex#2){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776
       class_mutex_intr_constructor include/linux/mutex.h:255 [inline]
       input_register_handle+0xca/0x630 drivers/input/input.c:2619
       kbd_connect+0xce/0x180 drivers/tty/vt/keyboard.c:1559
       input_attach_handler.isra.0+0x177/0x1e0 drivers/input/input.c:994
       input_register_device.cold+0x139/0x375 drivers/input/input.c:2378
       acpi_button_probe+0x5d3/0xbc0 drivers/acpi/button.c:622
       platform_probe+0x106/0x1d0 drivers/base/platform.c:1446
       call_driver_probe drivers/base/dd.c:583 [inline]
       really_probe+0x241/0xa60 drivers/base/dd.c:661
       __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833
       __driver_attach+0x2f4/0x6a0 drivers/base/dd.c:1227
       bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383
       bus_add_driver+0x305/0x5b0 drivers/base/bus.c:715
       driver_register+0x1e2/0x360 drivers/base/driver.c:249
       acpi_button_init+0xe4/0x100 drivers/acpi/button.c:759
       do_one_initcall+0x11d/0x760 init/main.c:1382
       do_initcall_level init/main.c:1444 [inline]
       do_initcalls init/main.c:1460 [inline]
       do_basic_setup init/main.c:1479 [inline]
       kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692
       kernel_init+0x1f/0x1e0 init/main.c:1582
       ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (input_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776
       class_mutex_intr_constructor include/linux/mutex.h:255 [inline]
       input_register_device.cold+0x5b/0x375 drivers/input/input.c:2374
       uinput_create_device drivers/input/misc/uinput.c:365 [inline]
       uinput_ioctl_handler.isra.0+0x8d8/0x1d10 drivers/input/misc/uinput.c:919
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:597 [inline]
       __se_sys_ioctl fs/ioctl.c:583 [inline]
       __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&newdev->mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776
       uinput_request_send drivers/input/misc/uinput.c:151 [inline]
       uinput_request_submit.part.0+0x25/0x2e0 drivers/input/misc/uinput.c:182
       uinput_request_submit drivers/input/misc/uinput.c:179 [inline]
       uinput_dev_upload_effect+0x174/0x1f0 drivers/input/misc/uinput.c:257
       input_ff_upload+0x578/0xc60 drivers/input/ff-core.c:148
       evdev_do_ioctl+0x1228/0x1b60 drivers/input/evdev.c:1181
       evdev_ioctl_handler drivers/input/evdev.c:1270 [inline]
       evdev_ioctl+0x16f/0x1a0 drivers/input/evdev.c:1279
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:597 [inline]
       __se_sys_ioctl fs/ioctl.c:583 [inline]
       __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ff->mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776
       class_mutex_constructor include/linux/mutex.h:253 [inline]
       input_ff_flush+0x63/0x1b0 drivers/input/ff-core.c:231
       uinput_dev_flush+0x2a/0x40 drivers/input/misc/uinput.c:283
       input_flush_device+0xc9/0x140 drivers/input/input.c:628
       evdev_release+0x344/0x420 drivers/input/evdev.c:435
       __fput+0x3ff/0xb40 fs/file_table.c:469
       fput_close_sync+0x118/0x250 fs/file_table.c:574
       __do_sys_close fs/open.c:1509 [inline]
       __se_sys_close fs/open.c:1494 [inline]
       __x64_sys_close+0x8b/0x120 fs/open.c:1494
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

2 locks held by udevd/5810:
 #0: ffff8880482d4118 (&evdev->mutex){+.+.}-{4:4}, at: evdev_release+0x79/0x420 drivers/input/evdev.c:432
 #1: ffff88802621e2c0 (&dev->mutex#2){+.+.}-{4:4}, at: class_mutex_intr_constructor include/linux/mutex.h:255 [inline]
 #1: ffff88802621e2c0 (&dev->mutex#2){+.+.}-{4:4}, at: input_flush_device+0x4a/0x140 drivers/input/input.c:626

stack backtrace:
CPU: 0 UID: 0 PID: 5810 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:614 [inline]
 __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776
 class_mutex_constructor include/linux/mutex.h:253 [inline]
 input_ff_flush+0x63/0x1b0 drivers/input/ff-core.c:231
 uinput_dev_flush+0x2a/0x40 drivers/input/misc/uinput.c:283
 input_flush_device+0xc9/0x140 drivers/input/input.c:628
 evdev_release+0x344/0x420 drivers/input/evdev.c:435
 __fput+0x3ff/0xb40 fs/file_table.c:469
 fput_close_sync+0x118/0x250 fs/file_table.c:574
 __do_sys_close fs/open.c:1509 [inline]
 __se_sys_close fs/open.c:1494 [inline]
 __x64_sys_close+0x8b/0x120 fs/open.c:1494
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f244f8a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc752a2690 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f244ffd6880 RCX: 00007f244f8a7407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007f244ffd66e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000016
R13: 00007ffc752a27a0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>