rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (1 GPs behind) idle=937/1/0x4000000000000000 softirq=199136/199137 fqs=5141 (t=10500 jiffies g=359765 q=1410) NMI backtrace for cpu 1 CPU: 1 PID: 7110 Comm: vhost-7108 Not tainted 5.15.0-rc3-next-20210930-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:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 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:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3889 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2608 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:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode+0x0/0x40 kernel/kcov.c:166 Code: 48 89 df e8 d2 63 46 00 e9 59 fe ff ff 48 8b 7c 24 08 e8 c3 63 46 00 e9 61 fd ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc <65> 8b 05 d9 34 8c 7e 89 c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 RSP: 0018:ffffc9000a97fae0 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff1100fcbf875 RSI: ffff88807904d700 RDI: 0000000000000003 RBP: 0000000000000000 R08: 000000000000000f R09: ffffc9000a97fb1f R10: ffffffff86c446f4 R11: 0000000000000000 R12: ffff88807e5fc380 R13: 000000000000000f R14: ffffffffffffffff R15: 0000000000000000 write_comp_data kernel/kcov.c:221 [inline] __sanitizer_cov_trace_cmp8+0x1d/0x70 kernel/kcov.c:267 vhost_iotlb_itree_iter_first drivers/vhost/iotlb.c:19 [inline] vhost_iotlb_itree_first+0xd4/0x280 drivers/vhost/iotlb.c:169 iotlb_access_ok+0x1ce/0x3e0 drivers/vhost/vhost.c:1336 vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366 handle_rx+0x145/0x1b40 drivers/vhost/net.c:1140 vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 48 89 df mov %rbx,%rdi 3: e8 d2 63 46 00 callq 0x4663da 8: e9 59 fe ff ff jmpq 0xfffffe66 d: 48 8b 7c 24 08 mov 0x8(%rsp),%rdi 12: e8 c3 63 46 00 callq 0x4663da 17: e9 61 fd ff ff jmpq 0xfffffd7d 1c: cc int3 1d: cc int3 1e: cc int3 1f: cc int3 20: cc int3 21: cc int3 22: cc int3 23: cc int3 24: cc int3 25: cc int3 26: cc int3 27: cc int3 28: cc int3 29: cc int3 * 2a: 65 8b 05 d9 34 8c 7e mov %gs:0x7e8c34d9(%rip),%eax # 0x7e8c350a <-- trapping instruction 31: 89 c2 mov %eax,%edx 33: 81 e2 00 01 00 00 and $0x100,%edx 39: a9 00 01 ff 00 test $0xff0100,%eax 3e: 74 10 je 0x50