syzbot

======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc7-syzkaller-00140-gec2df4364666 #0 Not tainted
------------------------------------------------------
syz-executor134/5831 is trying to acquire lock:
ffff88802a78a870 (&newdev->mutex){+.+.}-{4:4}, at: uinput_request_send drivers/input/misc/uinput.c:151 [inline]
ffff88802a78a870 (&newdev->mutex){+.+.}-{4:4}, at: uinput_request_submit.part.0+0x25/0x2e0 drivers/input/misc/uinput.c:182

but task is already holding lock:
ffff88802a7888b0 (&ff->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:225 [inline]
ffff88802a7888b0 (&ff->mutex){+.+.}-{4:4}, at: input_ff_upload+0x1dd/0xc10 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){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       class_mutex_constructor include/linux/mutex.h:225 [inline]
       input_ff_flush+0x63/0x180 drivers/input/ff-core.c:231
       uinput_dev_flush+0x2a/0x40 drivers/input/misc/uinput.c:283
       input_flush_device+0xa1/0x110 drivers/input/input.c:627
       evdev_release+0x344/0x420 drivers/input/evdev.c:435
       __fput+0x3ff/0xb70 fs/file_table.c:465
       fput_close_sync+0x118/0x260 fs/file_table.c:570
       __do_sys_close fs/open.c:1589 [inline]
       __se_sys_close fs/open.c:1574 [inline]
       __x64_sys_close+0x8b/0x120 fs/open.c:1574
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&dev->mutex#2){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       class_mutex_intr_constructor include/linux/mutex.h:227 [inline]
       input_register_handle+0xdc/0x620 drivers/input/input.c:2653
       kbd_connect+0xca/0x160 drivers/tty/vt/keyboard.c:1580
       input_attach_handler.isra.0+0x184/0x260 drivers/input/input.c:993
       input_register_device+0xa84/0x1130 drivers/input/input.c:2412
       acpi_button_add+0x582/0xb70 drivers/acpi/button.c:621
       acpi_device_probe+0xc6/0x330 drivers/acpi/bus.c:1076
       call_driver_probe drivers/base/dd.c:579 [inline]
       really_probe+0x23e/0xa90 drivers/base/dd.c:657
       __driver_probe_device+0x1de/0x440 drivers/base/dd.c:799
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:829
       __driver_attach+0x283/0x580 drivers/base/dd.c:1215
       bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:370
       bus_add_driver+0x2e9/0x690 drivers/base/bus.c:678
       driver_register+0x15c/0x4b0 drivers/base/driver.c:249
       __acpi_bus_register_driver+0xdf/0x130 drivers/acpi/bus.c:1027
       acpi_button_register_driver drivers/acpi/button.c:751 [inline]
       acpi_button_driver_init+0x82/0x110 drivers/acpi/button.c:760
       do_one_initcall+0x120/0x6e0 init/main.c:1274
       do_initcall_level init/main.c:1336 [inline]
       do_initcalls init/main.c:1352 [inline]
       do_basic_setup init/main.c:1371 [inline]
       kernel_init_freeable+0x5c2/0x900 init/main.c:1584
       kernel_init+0x1c/0x2b0 init/main.c:1474
       ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #1 (input_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       class_mutex_intr_constructor include/linux/mutex.h:227 [inline]
       input_register_device+0x98a/0x1130 drivers/input/input.c:2408
       uinput_create_device drivers/input/misc/uinput.c:365 [inline]
       uinput_ioctl_handler.isra.0+0x1357/0x1df0 drivers/input/misc/uinput.c:918
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:907 [inline]
       __se_sys_ioctl fs/ioctl.c:893 [inline]
       __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&newdev->mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain kernel/locking/lockdep.c:3911 [inline]
       __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
       lock_acquire kernel/locking/lockdep.c:5871 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       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+0x568/0xc10 drivers/input/ff-core.c:148
       evdev_do_ioctl+0xf40/0x1b30 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:907 [inline]
       __se_sys_ioctl fs/ioctl.c:893 [inline]
       __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 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:
  &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-executor134/5831:
 #0: ffff888024e04118 (&evdev->mutex){+.+.}-{4:4}, at: evdev_ioctl_handler drivers/input/evdev.c:1261 [inline]
 #0: ffff888024e04118 (&evdev->mutex){+.+.}-{4:4}, at: evdev_ioctl+0x7f/0x1a0 drivers/input/evdev.c:1279
 #1: ffff88802a7888b0 (&ff->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:225 [inline]
 #1: ffff88802a7888b0 (&ff->mutex){+.+.}-{4:4}, at: input_ff_upload+0x1dd/0xc10 drivers/input/ff-core.c:122

stack backtrace:
CPU: 0 UID: 0 PID: 5831 Comm: syz-executor134 Not tainted 6.16.0-rc7-syzkaller-00140-gec2df4364666 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046
 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain kernel/locking/lockdep.c:3911 [inline]
 __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
 lock_acquire kernel/locking/lockdep.c:5871 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
 __mutex_lock_common kernel/locking/mutex.c:602 [inline]
 __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
 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+0x568/0xc10 drivers/input/ff-core.c:148
 evdev_do_ioctl+0xf40/0x1b30 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:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ef0b13ca9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd2042fae8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 6e69752f7665642f RCX: 00007f8ef0b13ca9
RDX: 0000200000000300 RSI: 0000000040304580 RDI: 0000000000000004
RBP: 00007ffd2042fb08 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd2042fd68 R14: 0000000000000001 R15: 0000000000000001
 </TASK>