rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10499 ticks this GP) idle=c05/1/0x4000000000000000 softirq=39123/39123 fqs=5193 (t=10500 jiffies g=71665 q=3478) NMI backtrace for cpu 1 CPU: 1 PID: 1234 Comm: aoe_tx0 Not tainted 5.16.0-rc4-next-20211210-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+0x262/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3922 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2620 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:handle_tx+0x1d7/0x610 drivers/net/caif/caif_serial.c:236 Code: 24 d0 00 00 00 31 ff 44 89 fe 48 89 44 24 08 e8 4f 46 87 fc 45 84 ff 0f 85 5b 02 00 00 e8 61 42 87 fc 48 8b 44 24 28 80 38 00 <0f> 85 8c 03 00 00 49 8b 45 18 48 8d 78 38 48 89 fa 48 c1 ea 03 80 RSP: 0018:ffffc90005b5fb20 EFLAGS: 00000246 RAX: ffffed1008399003 RBX: ffff888029cf2d00 RCX: 0000000000000000 RDX: ffff88801d328000 RSI: ffffffff84f0b91f RDI: 0000000000000003 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff84f0b911 R11: 0000000000000000 R12: ffff88807f4a83c0 R13: ffff888041cc8000 R14: 0000000000000020 R15: 0000000000000000 __netdev_start_xmit include/linux/netdevice.h:4685 [inline] netdev_start_xmit include/linux/netdevice.h:4699 [inline] xmit_one net/core/dev.c:3473 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3489 __dev_queue_xmit+0x2983/0x3640 net/core/dev.c:4112 tx+0x68/0xb0 drivers/block/aoe/aoenet.c:63 kthread+0x1e7/0x3b0 drivers/block/aoe/aoecmd.c:1230 kthread+0x405/0x4f0 kernel/kthread.c:345 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 24 d0 and $0xd0,%al 2: 00 00 add %al,(%rax) 4: 00 31 add %dh,(%rcx) 6: ff 44 89 fe incl -0x2(%rcx,%rcx,4) a: 48 89 44 24 08 mov %rax,0x8(%rsp) f: e8 4f 46 87 fc callq 0xfc874663 14: 45 84 ff test %r15b,%r15b 17: 0f 85 5b 02 00 00 jne 0x278 1d: e8 61 42 87 fc callq 0xfc874283 22: 48 8b 44 24 28 mov 0x28(%rsp),%rax 27: 80 38 00 cmpb $0x0,(%rax) * 2a: 0f 85 8c 03 00 00 jne 0x3bc <-- trapping instruction 30: 49 8b 45 18 mov 0x18(%r13),%rax 34: 48 8d 78 38 lea 0x38(%rax),%rdi 38: 48 89 fa mov %rdi,%rdx 3b: 48 c1 ea 03 shr $0x3,%rdx 3f: 80 .byte 0x80