INFO: rcu detected stall in do_softirq

[syzbot]

Hello,

syzkaller hit the following crash on
8a4816cad00bf14642f0ed6043b32d29a05006ce
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
Unfortunately, I don't have any reproducer for this bug yet.


IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6a74da...@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.

Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable
INFO: rcu_sched detected stalls on CPUs/tasks:
(detected by 0, t=125007 jiffies, g=66299, c=66298, q=40)
All QSes seen, last rcu_sched kthread activity 125014
(4294991138-4294866124), jiffies_till_next_fqs=3, root ->qsmask 0x0
syz-executor5 R running task 22056 22277 3688 0x00000008
Call Trace:
<IRQ>
sched_show_task+0x4a3/0x5e0 kernel/sched/core.c:5198
print_other_cpu_stall+0x996/0x1090 kernel/rcu/tree.c:1564
check_cpu_stall.isra.61+0x6e6/0x15b0 kernel/rcu/tree.c:1682
__rcu_pending kernel/rcu/tree.c:3440 [inline]
rcu_pending kernel/rcu/tree.c:3502 [inline]
rcu_check_callbacks+0x256/0xd00 kernel/rcu/tree.c:2842
update_process_times+0x30/0x60 kernel/time/timer.c:1630
tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:162
tick_sched_timer+0x42/0x120 kernel/time/tick-sched.c:1166
__run_hrtimer kernel/time/hrtimer.c:1211 [inline]
__hrtimer_run_queues+0x358/0xe20 kernel/time/hrtimer.c:1275
hrtimer_interrupt+0x1c2/0x5e0 kernel/time/hrtimer.c:1309
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
smp_apic_timer_interrupt+0x14a/0x700 arch/x86/kernel/apic/apic.c:1050
apic_timer_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:904
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x50
RSP: 0018:ffff8801db206738 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff11
RAX: ffffed003a2965e3 RBX: ffff8801d14b2e40 RCX: ffffffff84c25899
RDX: 0000000000000100 RSI: ffff8801c5f47f29 RDI: 00000000000079c8
RBP: ffff8801db2067c8 R08: ffffed0038bea003 R09: ffffed0038bea003
R10: 000000000000000b R11: ffffed0038bea002 R12: ffff8801c5f40580
R13: ffff8801db206aa0 R14: 00000000000079d0 R15: dffffc0000000000
__xfrm_decode_session+0x68/0x110 net/xfrm/xfrm_policy.c:2358
__xfrm_policy_check+0x18c/0x2350 net/xfrm/xfrm_policy.c:2393
__xfrm_policy_check2 include/net/xfrm.h:1170 [inline]
xfrm_policy_check include/net/xfrm.h:1175 [inline]
xfrm6_policy_check include/net/xfrm.h:1185 [inline]
rawv6_rcv+0x8f6/0x1200 net/ipv6/raw.c:424
ipv6_raw_deliver net/ipv6/raw.c:224 [inline]
raw6_local_deliver+0x819/0xa80 net/ipv6/raw.c:240
ip6_input_finish+0x3c7/0x17a0 net/ipv6/ip6_input.c:246
NF_HOOK include/linux/netfilter.h:250 [inline]
ip6_input+0xe9/0x560 net/ipv6/ip6_input.c:327
dst_input include/net/dst.h:449 [inline]
ip6_rcv_finish+0x1a9/0x7a0 net/ipv6/ip6_input.c:71
NF_HOOK include/linux/netfilter.h:250 [inline]
ipv6_rcv+0xf37/0x1fa0 net/ipv6/ip6_input.c:208
__netif_receive_skb_core+0x1a41/0x3460 net/core/dev.c:4499
__netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4564
process_backlog+0x203/0x740 net/core/dev.c:5244
napi_poll net/core/dev.c:5642 [inline]
net_rx_action+0x792/0x1910 net/core/dev.c:5708
__do_softirq+0x2d7/0xb85 kernel/softirq.c:285
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1115
</IRQ>
do_softirq.part.21+0x14d/0x190 kernel/softirq.c:329
do_softirq kernel/softirq.c:177 [inline]
__local_bh_enable_ip+0x1ee/0x230 kernel/softirq.c:182
local_bh_enable include/linux/bottom_half.h:32 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:727 [inline]
ip6_finish_output2+0xba0/0x23a0 net/ipv6/ip6_output.c:121
ip6_fragment+0x25f2/0x3470 net/ipv6/ip6_output.c:739
ip6_finish_output+0x6bb/0xaf0 net/ipv6/ip6_output.c:152
NF_HOOK_COND include/linux/netfilter.h:239 [inline]
ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:171
dst_output include/net/dst.h:443 [inline]
ip6_local_out+0x95/0x160 net/ipv6/output_core.c:176
ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1674
ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1694
rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
rawv6_sendmsg+0x2ee9/0x3e70 net/ipv6/raw.c:935
inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
sock_sendmsg_nosec net/socket.c:628 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:638
SYSC_sendto+0x361/0x5c0 net/socket.c:1719
SyS_sendto+0x40/0x50 net/socket.c:1687
entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x452ac9
RSP: 002b:00007f042a550c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9
RDX: 0000000000000000 RSI: 0000000020aa7000 RDI: 0000000000000013
RBP: 00000000000004b6 R08: 00000000201e0000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f51b0
R13: 00000000ffffffff R14: 00007f042a5516d4 R15: 0000000000000000
rcu_sched kthread starved for 126236 jiffies! g66299 c66298 f0x2
RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_sched R running task 23456 8 2 0x80000000
Call Trace:
context_switch kernel/sched/core.c:2799 [inline]
__schedule+0x8eb/0x2060 kernel/sched/core.c:3375
schedule+0xf5/0x430 kernel/sched/core.c:3434
schedule_timeout+0x118/0x230 kernel/time/timer.c:1795
rcu_gp_kthread+0x9e5/0x1930 kernel/rcu/tree.c:2314
kthread+0x33c/0x400 kernel/kthread.c:238
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:515


---
This bug is generated by a dumb bot. It may contain errors.
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[Dmitry Vyukov]

On Fri, Jan 5, 2018 at 11:10 PM, syzbot
<syzbot+6a74da...@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzkaller hit the following crash on
> 8a4816cad00bf14642f0ed6043b32d29a05006ce
> git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> Unfortunately, I don't have any reproducer for this bug yet.
>
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+6a74da...@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.

Looks like a hang in xfrm, so +xfrm maintainers.

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[Dmitry Vyukov]

On Fri, Jan 5, 2018 at 11:14 PM, Dmitry Vyukov <dvy...@google.com> wrote:
> On Fri, Jan 5, 2018 at 11:10 PM, syzbot
> <syzbot+6a74da...@syzkaller.appspotmail.com> wrote:
>> Hello,
>>
>> syzkaller hit the following crash on
>> 8a4816cad00bf14642f0ed6043b32d29a05006ce
>> git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master
>> compiler: gcc (GCC) 7.1.1 20170620
>> .config is attached
>> Raw console output is attached.
>> Unfortunately, I don't have any reproducer for this bug yet.
>>
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+6a74da...@syzkaller.appspotmail.com
>> It will help syzbot understand when the bug is fixed. See footer for
>> details.
>> If you forward the report, please keep this part and the footer.
>
> Looks like a hang in xfrm, so +xfrm maintainers.

#syz dup: INFO: rcu detected stall in __xfrm_decode_session