rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=68e/1/0x4000000000000002 softirq=9893/9893 fqs=0 (t=10501 jiffies g=9057 q=95) rcu: rcu_preempt kthread starved for 10502 jiffies! g9057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt I29520 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x755/0x1580 kernel/sched/core.c:3880 schedule+0xd9/0x260 kernel/sched/core.c:3947 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807 rcu_gp_fqs_loop kernel/rcu/tree.c:1611 [inline] rcu_gp_kthread+0x9b2/0x18c0 kernel/rcu/tree.c:1768 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.3.0-rc8+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 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:2736 [inline] rcu_sched_clock_irq.cold+0x4dd/0xc13 kernel/rcu/tree.c:2183 update_process_times+0x32/0x80 kernel/time/timer.c:1639 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1106 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1131 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:__list_add include/linux/list.h:64 [inline] RIP: 0010:list_add_tail include/linux/list.h:93 [inline] RIP: 0010:list_move_tail include/linux/list.h:214 [inline] RIP: 0010:hhf_dequeue+0x69d/0xa20 net/sched/sch_hhf.c:439 Code: b0 e8 37 15 ac fb 0f b6 75 b0 40 84 f6 0f 84 c6 f9 ff ff e8 e5 13 ac fb 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 0f 85 08 03 00 00 <48> 89 d8 49 89 9d 98 03 00 00 48 c1 e8 03 42 80 3c 20 00 0f 85 b4 RSP: 0018:ffff8880a98b69a8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff1101243f10b RBX: ffff8880921f87b8 RCX: ffffffff85c660f9 RDX: 0000000000000100 RSI: ffffffff85c6610b RDI: 0000000000000001 RBP: ffff8880a98b69f8 R08: ffff8880a98a2240 R09: 0000000000000000 R10: fffffbfff134afaf R11: ffff8880a98a2240 R12: dffffc0000000000 R13: ffff8880921f84c0 R14: ffff8880921f8858 R15: ffff8880921f8850 dequeue_skb net/sched/sch_generic.c:258 [inline] qdisc_restart net/sched/sch_generic.c:361 [inline] __qdisc_run+0x1e7/0x19d0 net/sched/sch_generic.c:379 __dev_xmit_skb net/core/dev.c:3533 [inline] __dev_queue_xmit+0x16f1/0x3650 net/core/dev.c:3838 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902 br_dev_queue_push_xmit+0x3f3/0x5c0 net/bridge/br_forward.c:52 br_nf_dev_queue_xmit+0x34e/0x1470 net/bridge/br_netfilter_hooks.c:796 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] br_nf_post_routing+0x1502/0x1d30 net/bridge/br_netfilter_hooks.c:844 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:260 [inline] NF_HOOK include/linux/netfilter.h:303 [inline] br_forward_finish+0x215/0x400 net/bridge/br_forward.c:65 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015 br_nf_forward_finish+0x66c/0xa90 net/bridge/br_netfilter_hooks.c:560 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] br_nf_forward_ip net/bridge/br_netfilter_hooks.c:630 [inline] br_nf_forward_ip+0xc74/0x21e0 net/bridge/br_netfilter_hooks.c:571 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:260 [inline] NF_HOOK include/linux/netfilter.h:303 [inline] __br_forward+0x393/0xb00 net/bridge/br_forward.c:109 deliver_clone+0x61/0xc0 net/bridge/br_forward.c:125 br_flood+0x325/0x3d0 net/bridge/br_forward.c:232 br_handle_frame_finish+0xb46/0x1670 net/bridge/br_input.c:162 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015 br_nf_pre_routing_finish_ipv6+0x6fb/0xd80 net/bridge/br_netfilter_ipv6.c:206 NF_HOOK include/linux/netfilter.h:305 [inline] br_nf_pre_routing_ipv6+0x456/0x832 net/bridge/br_netfilter_ipv6.c:236 br_nf_pre_routing+0x1743/0x2355 net/bridge/br_netfilter_hooks.c:501 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_bridge_pre net/bridge/br_input.c:223 [inline] br_handle_frame+0x806/0x133e net/bridge/br_input.c:348 __netif_receive_skb_core+0xfc1/0x3060 net/core/dev.c:4905 __netif_receive_skb_one_core+0xa8/0x1a0 net/core/dev.c:5002 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5118 process_backlog+0x206/0x750 net/core/dev.c:5929 napi_poll net/core/dev.c:6352 [inline] net_rx_action+0x4d6/0x1030 net/core/dev.c:6418 __do_softirq+0x262/0x98c kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:603 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 9864 Comm: syz-executor784 Not tainted 5.3.0-rc8+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:31 [inline] RIP: 0010:atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] RIP: 0010:virt_spin_lock arch/x86/include/asm/qspinlock.h:83 [inline] RIP: 0010:native_queued_spin_lock_slowpath+0xb7/0x9f0 kernel/locking/qspinlock.c:325 Code: 01 00 00 00 49 c1 ee 03 41 83 e5 07 48 b8 00 00 00 00 00 fc ff df 49 01 c6 41 83 c5 03 be 04 00 00 00 48 89 df e8 c9 fd 52 00 <41> 0f b6 06 41 38 c5 7c 08 84 c0 0f 85 4e 07 00 00 44 8b 3b 45 85 RSP: 0018:ffff8880898072f8 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffff8880921f85a8 RCX: ffffffff81595bd7 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880921f85a8 RBP: ffff8880898073b8 R08: 1ffff1101243f0b5 R09: ffffed101243f0b6 R10: ffffed101243f0b5 R11: ffff8880921f85ab R12: 0000000000000001 R13: 0000000000000003 R14: ffffed101243f0b5 R15: 0000000000000001 FS: 0000555557368880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000610 CR3: 0000000092dde000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:654 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:50 [inline] queued_spin_lock include/asm-generic/qspinlock.h:81 [inline] do_raw_spin_lock+0x20e/0x2e0 kernel/locking/spinlock_debug.c:113 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline] _raw_spin_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] sch_tree_lock include/net/sch_generic.h:570 [inline] hhf_change+0x2e3/0xad0 net/sched/sch_hhf.c:537 qdisc_change net/sched/sch_api.c:1321 [inline] tc_modify_qdisc+0xfcf/0x1c50 net/sched/sch_api.c:1623 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5223 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:657 ___sys_sendmsg+0x803/0x920 net/socket.c:2311 __sys_sendmsg+0x105/0x1d0 net/socket.c:2356 __do_sys_sendmsg net/socket.c:2365 [inline] __se_sys_sendmsg net/socket.c:2363 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x442399 Code: e8 9c 07 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 3b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffe7090a7c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000442399 RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 0000000000030698 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000004032f0 R14: 0000000000000000 R15: 0000000000000000