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* INFO: rcu detected stall in addrconf_dad_work (5)
@ 2020-09-07 15:59 syzbot
  0 siblings, 0 replies; only message in thread
From: syzbot @ 2020-09-07 15:59 UTC (permalink / raw)
  To: davem, jhs, jiri, kuba, linux-kernel, netdev, syzkaller-bugs,
	vinicius.gomes, xiyou.wangcong


syzbot found the following issue on:

HEAD commit:    fc3abb53 Merge branch 'for-linus' of git://
git tree:       upstream
console output:
kernel config:
dashboard link:
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:
C reproducer:

The issue was bisected to:

commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22
Author: Vinicius Costa Gomes <>
Date:   Sat Sep 29 00:59:43 2018 +0000

    tc: Add support for configuring the taprio scheduler

bisection log:
console output:

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler")

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=786/1/0x4000000000000000 softirq=9770/9781 fqs=1 
	(detected by 0, t=10502 jiffies, g=8481, q=298)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7070 Comm: kworker/1:3 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
RIP: 0010:__lock_acquire+0xf4f/0x5570 kernel/locking/lockdep.c:4396
Code: ff ff 48 c7 c6 e0 d1 4b 88 48 c7 c7 20 a8 4b 88 e8 18 3d eb ff 0f 0b e9 31 fe ff ff 48 63 5c 24 10 be 08 00 00 00 48 8d 43 3f <48> 85 db 48 0f 49 c3 48 c1 f8 06 48 8d 3c c5 e0 49 5f 8c e8 f9 1d
RSP: 0018:ffffc90000da8b28 EFLAGS: 00000046
RAX: 00000000000006b6 RBX: 0000000000000677 RCX: 0000000000000008
RDX: 0000000000000004 RSI: 0000000000000008 RDI: ffffffff8c63f3d8
RBP: ffff88808dfd4a90 R08: 0000000000000000 R09: ffffffff8c5f4aaf
R10: fffffbfff18be955 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88808dfd4ab2 R14: ffff88808dfd4040 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004c9588 CR3: 0000000009a8d000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:354 [inline]
 advance_sched+0x4f/0x990 net/sched/sch_taprio.c:699
 __run_hrtimer kernel/time/hrtimer.c:1524 [inline]
 __hrtimer_run_queues+0x6a9/0xfc0 kernel/time/hrtimer.c:1588
 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline]
RIP: 0010:__call_rcu kernel/rcu/tree.c:2927 [inline]
RIP: 0010:call_rcu+0x3ac/0x7b0 kernel/rcu/tree.c:2968
Code: 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 b9 02 00 00 48 83 3d a8 b0 54 08 00 0f 84 1b 01 00 00 48 8b 3c 24 57 9d <0f> 1f 44 00 00 48 83 c4 20 5b 5d 41 5c 41 5d 41 5e 41 5f c3 80 3c
RSP: 0018:ffffc900061171c8 EFLAGS: 00000282
RAX: 1ffffffff136c789 RBX: ffff888092757bd8 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000402 RDI: 0000000000000282
RBP: ffff8880ae736ca8 R08: 0000000000000001 R09: ffffffff8c5f4a8f
R10: fffffbfff18be951 R11: 000000000000016e R12: ffff8880ae736c00
R13: ffff8880ae736c98 R14: ffff8880ae736c50 R15: 0000000000000033
 dst_release net/core/dst.c:179 [inline]
 dst_release+0x79/0xe0 net/core/dst.c:169
 refdst_drop include/net/dst.h:258 [inline]
 skb_dst_drop include/net/dst.h:270 [inline]
 skb_release_head_state+0x1f9/0x250 net/core/skbuff.c:648
 skb_release_all net/core/skbuff.c:662 [inline]
 __kfree_skb net/core/skbuff.c:678 [inline]
 kfree_skb.part.0+0x89/0x350 net/core/skbuff.c:696
 kfree_skb+0x7d/0x100 include/linux/refcount.h:270
 ip_tunnel_xmit+0x6ab/0x2ac3 net/ipv4/ip_tunnel.c:826
 erspan_xmit+0x1109/0x2760 net/ipv4/ip_gre.c:704
 __netdev_start_xmit include/linux/netdevice.h:4634 [inline]
 netdev_start_xmit include/linux/netdevice.h:4648 [inline]
 xmit_one net/core/dev.c:3561 [inline]
 dev_hard_start_xmit+0x193/0x950 net/core/dev.c:3577
 sch_direct_xmit+0x2e1/0xbd0 net/sched/sch_generic.c:313
 qdisc_restart net/sched/sch_generic.c:376 [inline]
 __qdisc_run+0x4b9/0x1620 net/sched/sch_generic.c:384
 qdisc_run include/net/pkt_sched.h:134 [inline]
 qdisc_run include/net/pkt_sched.h:126 [inline]
 __dev_xmit_skb net/core/dev.c:3752 [inline]
 __dev_queue_xmit+0x1456/0x2d60 net/core/dev.c:4105
 neigh_resolve_output net/core/neighbour.c:1489 [inline]
 neigh_resolve_output+0x3fe/0x6a0 net/core/neighbour.c:1469
 neigh_output include/net/neighbour.h:509 [inline]
 ip6_finish_output2+0x8ac/0x1780 net/ipv6/ip6_output.c:117
 __ip6_finish_output net/ipv6/ip6_output.c:143 [inline]
 __ip6_finish_output+0x447/0xab0 net/ipv6/ip6_output.c:128
 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x1db/0x520 net/ipv6/ip6_output.c:176
 dst_output include/net/dst.h:443 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ndisc_send_skb+0xa69/0x1720 net/ipv6/ndisc.c:506
 ndisc_send_ns+0x3a9/0x850 net/ipv6/ndisc.c:648
 addrconf_dad_work+0xc1c/0x1280 net/ipv6/addrconf.c:4115
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 0.000 msecs
rcu: rcu_preempt kthread starved for 10500 jiffies! g8481 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:29088 pid:   10 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0xea9/0x2230 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline]
 rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2058
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

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2020-09-07 15:59 INFO: rcu detected stall in addrconf_dad_work (5) syzbot

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