rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-...D } 2660 jiffies s: 81285 root: 0x1/. rcu: blocking rcu_node structures (internal RCU debug): Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 2550 Comm: udevd Not tainted 6.12.0-rc4-syzkaller-00052-gc6d9e43954bf #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:413 Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 31 f0 0d ff eb a0 e8 ba f0 0d RSP: 0018:ffffc90000006f58 EFLAGS: 00000002 RAX: 000000000000005b RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff82a08975 RDI: ffffffff93637660 RBP: ffffffff93637620 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 000000000000005b R14: ffffffff82a08910 R15: 0000000000000000 FS: 00007f69e3f3bc80(0000) GS:ffff8881f5800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c383a75 CR3: 0000000116584000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_out drivers/tty/serial/8250/8250.h:142 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3322 [inline] serial8250_console_write+0xf9e/0x17c0 drivers/tty/serial/8250/8250_port.c:3393 console_emit_next_record kernel/printk/printk.c:3092 [inline] console_flush_all+0x800/0xc60 kernel/printk/printk.c:3180 __console_flush_and_unlock kernel/printk/printk.c:3239 [inline] console_unlock+0xd9/0x210 kernel/printk/printk.c:3279 vprintk_emit+0x424/0x6f0 kernel/printk/printk.c:2407 vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:68 _printk+0xc8/0x100 kernel/printk/printk.c:2432 printk_stack_address arch/x86/kernel/dumpstack.c:72 [inline] show_trace_log_lvl+0x1b7/0x3d0 arch/x86/kernel/dumpstack.c:285 sched_show_task kernel/sched/core.c:7604 [inline] sched_show_task+0x3f0/0x5f0 kernel/sched/core.c:7579 show_state_filter+0xee/0x320 kernel/sched/core.c:7649 k_spec drivers/tty/vt/keyboard.c:667 [inline] k_spec+0xed/0x150 drivers/tty/vt/keyboard.c:656 kbd_keycode drivers/tty/vt/keyboard.c:1522 [inline] kbd_event+0xcbd/0x17a0 drivers/tty/vt/keyboard.c:1541 input_handler_events_default+0x116/0x1b0 drivers/input/input.c:2549 input_pass_values+0x777/0x8e0 drivers/input/input.c:126 input_event_dispose drivers/input/input.c:352 [inline] input_handle_event+0xb30/0x14d0 drivers/input/input.c:369 input_event drivers/input/input.c:398 [inline] input_event+0x83/0xa0 drivers/input/input.c:390 hidinput_hid_event+0xa12/0x2410 drivers/hid/hid-input.c:1719 hid_process_event+0x4b7/0x5e0 drivers/hid/hid-core.c:1540 hid_input_array_field+0x535/0x710 drivers/hid/hid-core.c:1652 hid_process_report drivers/hid/hid-core.c:1694 [inline] hid_report_raw_event+0xa02/0x11c0 drivers/hid/hid-core.c:2040 __hid_input_report.constprop.0+0x341/0x440 drivers/hid/hid-core.c:2110 hid_irq_in+0x35e/0x870 drivers/hid/usbhid/hid-core.c:285 __usb_hcd_giveback_urb+0x389/0x6e0 drivers/usb/core/hcd.c:1650 usb_hcd_giveback_urb+0x396/0x450 drivers/usb/core/hcd.c:1734 dummy_timer+0x17f0/0x3930 drivers/usb/gadget/udc/dummy_hcd.c:1993 __run_hrtimer kernel/time/hrtimer.c:1691 [inline] __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1755 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1772 handle_softirqs+0x206/0x8d0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xac/0x110 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:syscall_exit_to_user_mode_prepare+0x0/0x260 kernel/entry/common.c:181 Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <41> 55 65 48 8b 05 96 a9 c3 7e 41 54 55 53 48 89 fb 48 8b 68 08 4c RSP: 0018:ffffc9000173ff00 EFLAGS: 00000296 RAX: 0000000000000000 RBX: ffffc9000173ff58 RCX: ffffffff85d05cfa RDX: ffff888115cbd7c0 RSI: ffffffff85d05d09 RDI: ffffc9000173ff58 RBP: ffffc9000173ff58 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000002f R13: 000000000000002f R14: 0000000000000000 R15: 0000000000000000 __syscall_exit_to_user_mode_work kernel/entry/common.c:205 [inline] syscall_exit_to_user_mode+0x11/0x260 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f69e407491e Code: ff 89 ef 48 89 04 24 e8 4f 57 f9 ff 48 8b 04 24 48 83 c4 30 5d c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 21 b8 2f 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 70 48 8b 15 db c4 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007fff83039788 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00007f69e407491e RDX: 0000000000000040 RSI: 00007fff83039850 RDI: 0000000000000009 RBP: 00007fff83039850 R08: 00000000957c8e6e R09: 00007f69e4481080 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000200000001 R14: 0000000000000000 R15: 0000000000000000 do_group_exit+0xd3/0x2a0 kernel/exit.c:1088 __do_sys_exit_group kernel/exit.c:1099 [inline] __se_sys_exit_group kernel/exit.c:1097 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1097 x64_sys_call+0x14a9/0x16a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f09ca907a90 RSP: 002b:00007ffc43f2e658 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f09ca9f8860 RCX: 00007f09ca907a90 RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000001 RBP: 00007f09ca9f8860 R08: 0000000000000001 R09: 493fa5feda35867a R10: 00007ffc43f2e510 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f09ca9fc658 R15: 0000000000000001 task:kworker/u8:0 state:R running task stack:32568 pid:30696 tgid:30696 ppid:14160 flags:0x00004000 Call Trace: ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 task:kworker/u8:2 state:R running task stack:32568 pid:30697 tgid:30697 ppid:30236 flags:0x00004000 Call Trace: Showing all locks held in the system: 4 locks held by udevd/2550: #0: ffff88813265e230 (&dev->event_lock ){..-.}-{2:2} , at: input_event drivers/input/input.c:397 [inline] , at: input_event+0x70/0xa0 drivers/input/input.c:390 #1: ffffffff88ebb140 ( rcu_read_lock ){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] ){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] ){....}-{1:2}, at: input_pass_values+0x8b/0x8e0 drivers/input/input.c:118 #2: ffffffff89387a58 (kbd_event_lock){..-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffffffff89387a58 (kbd_event_lock){..-.}-{2:2}, at: kbd_event+0x8a/0x17a0 drivers/tty/vt/keyboard.c:1535 #3: ffffffff88ebb140 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #3: ffffffff88ebb140 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #3: ffffffff88ebb140 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6720 2 locks held by getty/2608: #0: ffff88810f7470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 1 lock held by syz.1.5463/30211: #0: ffffffff88ec6a38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x282/0x3b0 kernel/rcu/tree_exp.h:297 1 lock held by syz.3.5464/30213: #0: ffffffff88ec6a38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x1a4/0x3b0 kernel/rcu/tree_exp.h:329 =============================================