input: syz1 as /devices/virtual/input/input186 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.201/7027 is trying to acquire lock: ffff0000d7b53870 (&newdev->mutex){+.+.}-{4:4}, at: uinput_request_send drivers/input/misc/uinput.c:151 [inline] ffff0000d7b53870 (&newdev->mutex){+.+.}-{4:4}, at: uinput_request_submit+0x168/0x600 drivers/input/misc/uinput.c:182 but task is already holding lock: ffff0000cf8a24b0 (&ff->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] ffff0000cf8a24b0 (&ff->mutex){+.+.}-{4:4}, at: input_ff_upload+0x2f0/0x924 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+0x1d0/0x2678 kernel/locking/mutex.c:614 __mutex_lock kernel/locking/mutex.c:776 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:828 class_mutex_constructor include/linux/mutex.h:253 [inline] input_ff_flush+0x64/0x198 drivers/input/ff-core.c:231 uinput_dev_flush+0x30/0x4c drivers/input/misc/uinput.c:283 input_flush_device+0xb8/0x110 drivers/input/input.c:628 evdev_release+0xc8/0x608 drivers/input/evdev.c:435 __fput+0x340/0x75c fs/file_table.c:468 fput_close_sync+0x100/0x264 fs/file_table.c:573 __do_sys_close fs/open.c:1573 [inline] __se_sys_close fs/open.c:1558 [inline] __arm64_sys_close+0x7c/0x118 fs/open.c:1558 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #2 (&dev->mutex#2){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:614 __mutex_lock kernel/locking/mutex.c:776 [inline] mutex_lock_interruptible_nested+0x2c/0x38 kernel/locking/mutex.c:851 class_mutex_intr_constructor include/linux/mutex.h:255 [inline] input_register_handle+0x104/0x42c drivers/input/input.c:2619 kbd_connect+0xbc/0x14c drivers/tty/vt/keyboard.c:1559 input_attach_handler drivers/input/input.c:994 [inline] input_register_device+0xaa4/0xe90 drivers/input/input.c:2378 acpi_button_add+0x580/0x97c drivers/acpi/button.c:621 acpi_device_probe+0xa8/0x2d4 drivers/acpi/bus.c:1076 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x3b4/0xa00 drivers/base/dd.c:659 __driver_probe_device+0x180/0x2f8 drivers/base/dd.c:801 driver_probe_device+0x6c/0x1a4 drivers/base/dd.c:831 __driver_attach+0x2d4/0x564 drivers/base/dd.c:1225 bus_for_each_dev+0x204/0x290 drivers/base/bus.c:383 driver_attach+0x4c/0x5c drivers/base/dd.c:1243 bus_add_driver+0x2e4/0x5ec drivers/base/bus.c:715 driver_register+0x220/0x30c drivers/base/driver.c:249 __acpi_bus_register_driver+0xc8/0x108 drivers/acpi/bus.c:1027 acpi_button_register_driver drivers/acpi/button.c:753 [inline] acpi_button_driver_init+0x9c/0xd8 drivers/acpi/button.c:762 do_one_initcall+0x248/0x9b4 init/main.c:1378 do_initcall_level+0x128/0x1c4 init/main.c:1440 do_initcalls+0x70/0xd0 init/main.c:1456 do_basic_setup+0x78/0x8c init/main.c:1475 kernel_init_freeable+0x268/0x39c init/main.c:1688 kernel_init+0x24/0x1dc init/main.c:1578 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 -> #1 (input_mutex){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:614 __mutex_lock kernel/locking/mutex.c:776 [inline] mutex_lock_interruptible_nested+0x2c/0x38 kernel/locking/mutex.c:851 class_mutex_intr_constructor include/linux/mutex.h:255 [inline] input_register_device+0x8b0/0xe90 drivers/input/input.c:2374 uinput_create_device+0x350/0x518 drivers/input/misc/uinput.c:365 uinput_ioctl_handler+0x404/0x1340 drivers/input/misc/uinput.c:919 uinput_ioctl+0x38/0x4c drivers/input/misc/uinput.c:1090 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #0 (&newdev->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+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:614 __mutex_lock kernel/locking/mutex.c:776 [inline] mutex_lock_interruptible_nested+0x2c/0x38 kernel/locking/mutex.c:851 uinput_request_send drivers/input/misc/uinput.c:151 [inline] uinput_request_submit+0x168/0x600 drivers/input/misc/uinput.c:182 uinput_dev_upload_effect+0x130/0x1c0 drivers/input/misc/uinput.c:257 input_ff_upload+0x4cc/0x924 drivers/input/ff-core.c:148 evdev_do_ioctl drivers/input/evdev.c:1181 [inline] evdev_ioctl_handler+0x18bc/0x2214 drivers/input/evdev.c:1270 evdev_ioctl+0x38/0x4c 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] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 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.0.201/7027: #0: ffff0000dc529118 (&evdev->mutex){+.+.}-{4:4}, at: evdev_ioctl_handler+0x114/0x2214 drivers/input/evdev.c:1261 #1: ffff0000cf8a24b0 (&ff->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #1: ffff0000cf8a24b0 (&ff->mutex){+.+.}-{4:4}, at: input_ff_upload+0x2f0/0x924 drivers/input/ff-core.c:122 stack backtrace: CPU: 1 UID: 0 PID: 7027 Comm: syz.0.201 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043 check_noncircular+0x154/0x174 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+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:614 __mutex_lock kernel/locking/mutex.c:776 [inline] mutex_lock_interruptible_nested+0x2c/0x38 kernel/locking/mutex.c:851 uinput_request_send drivers/input/misc/uinput.c:151 [inline] uinput_request_submit+0x168/0x600 drivers/input/misc/uinput.c:182 uinput_dev_upload_effect+0x130/0x1c0 drivers/input/misc/uinput.c:257 input_ff_upload+0x4cc/0x924 drivers/input/ff-core.c:148 evdev_do_ioctl drivers/input/evdev.c:1181 [inline] evdev_ioctl_handler+0x18bc/0x2214 drivers/input/evdev.c:1270 evdev_ioctl+0x38/0x4c 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] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596