rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (1 GPs behind) idle=21b/1/0x4000000000000000 softirq=52927/52928 fqs=5087 (t=10500 jiffies g=92801 q=673) NMI backtrace for cpu 1 CPU: 1 PID: 1228 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:handle_tx+0x138/0x610 drivers/net/caif/caif_serial.c:225 Code: 8b 63 30 4c 39 64 24 10 0f 84 95 02 00 00 e8 5f 85 93 fc 4d 85 e4 0f 84 87 02 00 00 e8 51 85 93 fc 49 8d 44 24 70 48 89 04 24 <48> c1 e8 03 0f b6 04 28 84 c0 74 08 3c 03 0f 8e d9 03 00 00 4c 89 RSP: 0000:ffffc900053b7b20 EFLAGS: 00000293 RAX: ffff888075a56b30 RBX: ffff888070e4ac80 RCX: 0000000000000000 RDX: ffff88801dd56140 RSI: ffffffff84e35f8f RDI: 0000000000000003 RBP: dffffc0000000000 R08: 0000000000000000 R09: 00000000471c0b00 R10: ffffffff84e361dc R11: 0000000000000000 R12: ffff888075a56ac0 R13: ffff88801e206000 R14: 0000000000000020 R15: ffff888070e4a000 __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): 0: 8b 63 30 mov 0x30(%rbx),%esp 3: 4c 39 64 24 10 cmp %r12,0x10(%rsp) 8: 0f 84 95 02 00 00 je 0x2a3 e: e8 5f 85 93 fc callq 0xfc938572 13: 4d 85 e4 test %r12,%r12 16: 0f 84 87 02 00 00 je 0x2a3 1c: e8 51 85 93 fc callq 0xfc938572 21: 49 8d 44 24 70 lea 0x70(%r12),%rax 26: 48 89 04 24 mov %rax,(%rsp) * 2a: 48 c1 e8 03 shr $0x3,%rax <-- trapping instruction 2e: 0f b6 04 28 movzbl (%rax,%rbp,1),%eax 32: 84 c0 test %al,%al 34: 74 08 je 0x3e 36: 3c 03 cmp $0x3,%al 38: 0f 8e d9 03 00 00 jle 0x417 3e: 4c rex.WR 3f: 89 .byte 0x89