rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10498 ticks this GP) idle=cb1/1/0x4000000000000000 softirq=40819/40819 fqs=5173 (t=10500 jiffies g=64513 q=1338) NMI backtrace for cpu 1 CPU: 1 PID: 1223 Comm: aoe_tx0 Not tainted 5.16.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194 Code: 74 24 10 e8 ea 7f 15 f8 48 89 ef e8 32 f6 15 f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 23 be 08 f8 65 8b 05 ec 30 bb 76 85 c0 74 0a 5b 5d c3 e8 90 b0 RSP: 0018:ffffc9000546fab8 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000200 RCX: 1ffffffff1ffeb86 RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000001 RBP: ffffffff9078e3d8 R08: 0000000000000001 R09: ffffffff8ff74b57 R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffff R13: ffff888040b73001 R14: 0000000000000020 R15: 0000000000000020 spin_unlock_irqrestore include/linux/spinlock.h:404 [inline] uart_write_room+0x174/0x2f0 drivers/tty/serial/serial_core.c:611 tty_write_room+0x61/0x80 drivers/tty/tty_ioctl.c:79 handle_tx+0x159/0x610 drivers/net/caif/caif_serial.c:226 __netdev_start_xmit include/linux/netdevice.h:4994 [inline] netdev_start_xmit include/linux/netdevice.h:5008 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3606 __dev_queue_xmit+0x299a/0x3650 net/core/dev.c:4229 tx+0x68/0xb0 drivers/block/aoe/aoenet.c:63 kthread+0x1e7/0x3b0 drivers/block/aoe/aoecmd.c:1230 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 24 10 and $0x10,%al 2: e8 ea 7f 15 f8 callq 0xf8157ff1 7: 48 89 ef mov %rbp,%rdi a: e8 32 f6 15 f8 callq 0xf815f641 f: 81 e3 00 02 00 00 and $0x200,%ebx 15: 75 25 jne 0x3c 17: 9c pushfq 18: 58 pop %rax 19: f6 c4 02 test $0x2,%ah 1c: 75 2d jne 0x4b 1e: 48 85 db test %rbx,%rbx 21: 74 01 je 0x24 23: fb sti 24: bf 01 00 00 00 mov $0x1,%edi * 29: e8 23 be 08 f8 callq 0xf808be51 <-- trapping instruction 2e: 65 8b 05 ec 30 bb 76 mov %gs:0x76bb30ec(%rip),%eax # 0x76bb3121 35: 85 c0 test %eax,%eax 37: 74 0a je 0x43 39: 5b pop %rbx 3a: 5d pop %rbp 3b: c3 retq 3c: e8 .byte 0xe8 3d: 90 nop 3e: b0 .byte 0xb0