rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=1eb/1/0x4000000000000000 softirq=67614/67615 fqs=444 (t=10502 jiffies g=89061 q=322) rcu: rcu_preempt kthread starved for 9614 jiffies! g89061 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:28944 pid: 16 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5073 [inline] __schedule+0xa9a/0x4cc0 kernel/sched/core.c:6388 schedule+0xd2/0x1f0 kernel/sched/core.c:6460 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1884 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1971 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2144 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:115 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x1c6/0x250 drivers/acpi/processor_idle.c:556 NMI backtrace for cpu 0 CPU: 0 PID: 1229 Comm: aoe_tx0 Not tainted 5.18.0-rc4-syzkaller-00006-gd615b5416f8a #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+0x1e6/0x230 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:639 [inline] check_cpu_stall kernel/rcu/tree_stall.h:723 [inline] rcu_pending kernel/rcu/tree.c:3923 [inline] rcu_sched_clock_irq.cold+0xa1/0x8d6 kernel/rcu/tree.c:2625 update_process_times+0x16d/0x200 kernel/time/timer.c:1788 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:243 tick_sched_timer+0xee/0x120 kernel/time/tick-sched.c:1473 __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:645 RIP: 0010:check_kcov_mode+0x2c/0x40 kernel/kcov.c:177 Code: 05 19 0f 8a 7e 89 c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b 96 a4 15 00 00 85 d2 74 0b 8b 86 80 15 00 00 <39> f8 0f 94 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 31 c0 RSP: 0018:ffffc90005067af0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88801e998000 RDI: 0000000000000003 RBP: ffff8880781d7e80 R08: 0000000000000020 R09: 000000001bba0c00 R10: ffffffff8740b4a1 R11: 0000000000000000 R12: 0000000000000020 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88801b07a000 write_comp_data kernel/kcov.c:221 [inline] __sanitizer_cov_trace_cmp4+0x1c/0x70 kernel/kcov.c:261 __skb_pull include/linux/skbuff.h:2550 [inline] skb_pull_inline include/linux/skbuff.h:2556 [inline] skb_pull+0x91/0x110 net/core/skbuff.c:2056 handle_tx+0x355/0x610 drivers/net/caif/caif_serial.c:249 __netdev_start_xmit include/linux/netdevice.h:4778 [inline] netdev_start_xmit include/linux/netdevice.h:4792 [inline] xmit_one net/core/dev.c:3532 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3548 __dev_queue_xmit+0x2b81/0x39c0 net/core/dev.c:4176 tx+0x68/0xb0 drivers/block/aoe/aoenet.c:63 kthread+0x1e7/0x3b0 drivers/block/aoe/aoecmd.c:1229 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 ---------------- Code disassembly (best guess): 0: 05 19 0f 8a 7e add $0x7e8a0f19,%eax 5: 89 c2 mov %eax,%edx 7: 81 e2 00 01 00 00 and $0x100,%edx d: a9 00 01 ff 00 test $0xff0100,%eax 12: 74 10 je 0x24 14: 31 c0 xor %eax,%eax 16: 85 d2 test %edx,%edx 18: 74 15 je 0x2f 1a: 8b 96 a4 15 00 00 mov 0x15a4(%rsi),%edx 20: 85 d2 test %edx,%edx 22: 74 0b je 0x2f 24: 8b 86 80 15 00 00 mov 0x1580(%rsi),%eax * 2a: 39 f8 cmp %edi,%eax <-- trapping instruction 2c: 0f 94 c0 sete %al 2f: c3 retq 30: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 37: 00 00 00 00 3b: 0f 1f 00 nopl (%rax) 3e: 31 c0 xor %eax,%eax