rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 2-....: (10499 ticks this GP) idle=7a2/1/0x4000000000000004 softirq=7011/7012 fqs=5196 (t=10500 jiffies g=5421 q=1918) NMI backtrace for cpu 2 CPU: 2 PID: 7873 Comm: syz-executor.4 Not tainted 5.4.0-syzkaller #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq.cold+0x509/0xc02 kernel/rcu/tree.c:2271 update_process_times+0x2d/0x70 kernel/time/timer.c:1726 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:kmem_cache_free+0xab/0x320 mm/slab.c:3694 Code: e8 ba 26 00 00 84 c0 74 77 41 f7 c6 00 02 00 00 74 4f e8 08 a4 c8 ff 48 83 3d 58 70 61 07 00 0f 84 fa 01 00 00 4c 89 f7 57 9d <0f> 1f 44 00 00 4c 8b 6d 08 0f 1f 44 00 00 65 8b 05 38 ef 4f 7e 83 RSP: 0018:ffff88802d709138 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: ffff88801f51ae00 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000282 RBP: ffff88802d709158 R08: 1ffffffff15377ba R09: fffffbfff15377bb R10: fffffbfff15377ba R11: ffffffff8a9bbdd7 R12: ffff88807ea26c40 R13: ffffffff85c6d5cb R14: 0000000000000282 R15: ffffffff86556e74 kfree_skbmem net/core/skbuff.c:623 [inline] kfree_skbmem+0xfb/0x1c0 net/core/skbuff.c:617 __kfree_skb net/core/skbuff.c:680 [inline] kfree_skb net/core/skbuff.c:697 [inline] kfree_skb+0x109/0x420 net/core/skbuff.c:691 ip_tunnel_xmit+0x6d4/0x2d0c net/ipv4/ip_tunnel.c:828 __gre_xmit+0x5e9/0x9a0 net/ipv4/ip_gre.c:448 gre_tap_xmit+0x3e5/0x660 net/ipv4/ip_gre.c:711 __netdev_start_xmit include/linux/netdevice.h:4442 [inline] netdev_start_xmit include/linux/netdevice.h:4456 [inline] xmit_one net/core/dev.c:3420 [inline] dev_hard_start_xmit+0x1a3/0x9b0 net/core/dev.c:3436 sch_direct_xmit+0x372/0xd30 net/sched/sch_generic.c:313 __dev_xmit_skb net/core/dev.c:3621 [inline] __dev_queue_xmit+0x2707/0x35c0 net/core/dev.c:3982 dev_queue_xmit+0x18/0x20 net/core/dev.c:4046 neigh_resolve_output net/core/neighbour.c:1490 [inline] neigh_resolve_output+0x5c4/0x990 net/core/neighbour.c:1470 neigh_output include/net/neighbour.h:511 [inline] ip6_finish_output2+0x109a/0x25c0 net/ipv6/ip6_output.c:116 __ip6_finish_output+0x444/0xaa0 net/ipv6/ip6_output.c:142 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x25e/0x880 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0xf1f/0x1490 net/ipv6/ndisc.c:505 ndisc_send_rs+0x134/0x720 net/ipv6/ndisc.c:699 addrconf_rs_timer+0x30f/0x6e0 net/ipv6/addrconf.c:3879 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:generic_exec_single+0x33a/0x4c0 kernel/smp.c:155 Code: 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 68 01 00 00 48 83 3d 2e 81 a9 07 00 0f 84 e0 00 00 00 e8 eb 2a 0b 00 48 89 df 57 9d <0f> 1f 44 00 00 45 31 ed e9 39 fe ff ff e8 d4 2a 0b 00 0f 0b e9 23 RSP: 0018:ffff888012defa80 EFLAGS: 00000216 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: 0000000000000216 RCX: ffffc9000f087000 RDX: 0000000000001b95 RSI: ffffffff8169b335 RDI: 0000000000000216 RBP: ffff888012defab0 R08: 1ffffffff15377bb R09: fffffbfff15377bc R10: fffffbfff15377bb R11: ffffffff8a9bbddf R12: 0000000000000200 R13: ffff888012defb00 R14: ffff888012defbd0 R15: ffffffff818bd170 smp_call_function_single+0x17c/0x480 kernel/smp.c:308 task_function_call+0xe9/0x180 kernel/events/core.c:114 perf_install_in_context+0x308/0x5a0 kernel/events/core.c:2746 __do_sys_perf_event_open+0x1cbc/0x2c70 kernel/events/core.c:11543 __se_sys_perf_event_open kernel/events/core.c:11151 [inline] __x64_sys_perf_event_open+0xbe/0x150 kernel/events/core.c:11151 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a759 Code: bd b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 8b b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1dde0ffc88 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 000000000071bf00 RCX: 000000000045a759 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 000000002001d000 RBP: 0000000000000005 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 00007f1dde1006d4 R13: 00000000004aec17 R14: 00000000006f1cb0 R15: 00000000ffffffff