====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.2.5350/28203 is trying to acquire lock: ffff88802fe7c070 (&newdev->mutex){+.+.}-{4:4}, at: uinput_request_send drivers/input/misc/uinput.c:151 [inline] ffff88802fe7c070 (&newdev->mutex){+.+.}-{4:4}, at: uinput_request_submit+0x1bd/0x740 drivers/input/misc/uinput.c:182 but task is already holding lock: ffff88802fe7d0b0 (&ff->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] ffff88802fe7d0b0 (&ff->mutex){+.+.}-{4:4}, at: input_ff_upload+0x398/0xb80 drivers/input/ff-core.c:122 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&ff->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 class_mutex_constructor include/linux/mutex.h:253 [inline] input_ff_flush+0x5e/0x1a0 drivers/input/ff-core.c:231 input_flush_device+0xd6/0x130 drivers/input/input.c:628 evdev_release+0xe1/0x800 drivers/input/evdev.c:435 __fput+0x44f/0xa70 fs/file_table.c:468 fput_close_sync+0x11f/0x240 fs/file_table.c:573 __do_sys_close fs/open.c:1573 [inline] __se_sys_close fs/open.c:1558 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1558 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&dev->mutex#2){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 class_mutex_constructor include/linux/mutex.h:253 [inline] input_disconnect_device drivers/input/input.c:703 [inline] __input_unregister_device+0x31/0x640 drivers/input/input.c:2185 input_unregister_device+0x9b/0x100 drivers/input/input.c:2418 uinput_destroy_device+0x6c1/0x8c0 drivers/input/misc/uinput.c:299 uinput_ioctl_handler+0x73c/0x14a0 drivers/input/misc/uinput.c:923 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 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:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 uinput_request_send drivers/input/misc/uinput.c:151 [inline] uinput_request_submit+0x1bd/0x740 drivers/input/misc/uinput.c:182 uinput_dev_upload_effect+0x182/0x230 drivers/input/misc/uinput.c:257 input_ff_upload+0x5fb/0xb80 drivers/input/ff-core.c:148 evdev_do_ioctl drivers/input/evdev.c:1181 [inline] evdev_ioctl_handler+0x16e2/0x1fe0 drivers/input/evdev.c:1270 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 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: &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.2.5350/28203: #0: ffff8880483f9118 (&evdev->mutex){+.+.}-{4:4}, at: evdev_ioctl_handler+0x14a/0x1fe0 drivers/input/evdev.c:1261 #1: ffff88802fe7d0b0 (&ff->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #1: ffff88802fe7d0b0 (&ff->mutex){+.+.}-{4:4}, at: input_ff_upload+0x398/0xb80 drivers/input/ff-core.c:122 stack backtrace: CPU: 0 UID: 0 PID: 28203 Comm: syz.2.5350 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776 uinput_request_send drivers/input/misc/uinput.c:151 [inline] uinput_request_submit+0x1bd/0x740 drivers/input/misc/uinput.c:182 uinput_dev_upload_effect+0x182/0x230 drivers/input/misc/uinput.c:257 input_ff_upload+0x5fb/0xb80 drivers/input/ff-core.c:148 evdev_do_ioctl drivers/input/evdev.c:1181 [inline] evdev_ioctl_handler+0x16e2/0x1fe0 drivers/input/evdev.c:1270 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f74b079acb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f74b1683028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f74b0a16090 RCX: 00007f74b079acb9 RDX: 00002000000001c0 RSI: 0000000040304580 RDI: 000000000000000c RBP: 00007f74b0808bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f74b0a16128 R14: 00007f74b0a16090 R15: 00007f74b0b3fa48