INFO: rcu detected stall in ipv6_rcv (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 13bf6d6a Add linux-next specific files for 20190725
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16c5cd94600000
kernel config: https://syzkaller.appspot.com/x/.config?x=8ae987d803395886
dashboard link: https://syzkaller.appspot.com/bug?extid=34f3e3f781b524b5127a
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15e55df4600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=142f7768600000

The bug was bisected to:

commit ccf355e52a3265624b7acadd693c849d599e9b9f
Author: Fuqian Huang <huangfq...@gmail.com>
Date: Mon Jul 8 12:34:17 2019 +0000

net: phy: Make use of linkmode_mod_bit helper

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12285f58600000
final crash: https://syzkaller.appspot.com/x/report.txt?x=11285f58600000
console output: https://syzkaller.appspot.com/x/log.txt?x=16285f58600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+34f3e3...@syzkaller.appspotmail.com
Fixes: ccf355e52a32 ("net: phy: Make use of linkmode_mod_bit helper")

TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending
cookies. Check SNMP counters.
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (1 GPs behind) idle=c0a/1/0x4000000000000002
softirq=11627/11628 fqs=5250
(t=10500 jiffies g=10477 q=33)
NMI backtrace for cpu 1
CPU: 1 PID: 10160 Comm: syz-executor291 Not tainted 5.3.0-rc1-next-20190725
#52
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__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:1068 [inline]
smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1093
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
RIP: 0010:cpu_relax arch/x86/include/asm/processor.h:656 [inline]
RIP: 0010:virt_spin_lock arch/x86/include/asm/qspinlock.h:84 [inline]
RIP: 0010:native_queued_spin_lock_slowpath+0x132/0x9f0
kernel/locking/qspinlock.c:325
Code: 00 00 00 48 8b 45 d0 65 48 33 04 25 28 00 00 00 0f 85 37 07 00 00 48
81 c4 98 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 f3 90 <e9> 73 ff ff ff
8b 45 98 4c 8d 65 d8 3d 00 01 00 00 0f 84 e5 00 00
RSP: 0018:ffff8880ae909210 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff88809338ad08 RCX: ffffffff81599777
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88809338ad08
RBP: ffff8880ae9092d0 R08: 1ffff110126715a1 R09: ffffed10126715a2
R10: ffffed10126715a1 R11: ffff88809338ad0b R12: 0000000000000001
R13: 0000000000000003 R14: ffffed10126715a1 R15: 0000000000000001
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:642 [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]
release_sock+0x20/0x1c0 net/core/sock.c:2932
wait_on_pending_writer+0x20f/0x420 net/tls/tls_main.c:91
tls_sk_proto_cleanup+0x2c5/0x3e0 net/tls/tls_main.c:295
tls_sk_proto_unhash+0x90/0x3f0 net/tls/tls_main.c:330
tcp_set_state+0x5b9/0x7d0 net/ipv4/tcp.c:2235
tcp_done+0xe2/0x320 net/ipv4/tcp.c:3824
tcp_reset+0x132/0x500 net/ipv4/tcp_input.c:4080
tcp_validate_incoming+0xa2d/0x1660 net/ipv4/tcp_input.c:5440
tcp_rcv_established+0x6b5/0x1e70 net/ipv4/tcp_input.c:5648
tcp_v6_do_rcv+0x41e/0x12c0 net/ipv6/tcp_ipv6.c:1356
tcp_v6_rcv+0x31f1/0x3500 net/ipv6/tcp_ipv6.c:1588
ip6_protocol_deliver_rcu+0x2fe/0x1660 net/ipv6/ip6_input.c:397
ip6_input_finish+0x84/0x170 net/ipv6/ip6_input.c:438
NF_HOOK include/linux/netfilter.h:305 [inline]
NF_HOOK include/linux/netfilter.h:299 [inline]
ip6_input+0xe4/0x3f0 net/ipv6/ip6_input.c:447
dst_input include/net/dst.h:442 [inline]
ip6_rcv_finish+0x1de/0x2f0 net/ipv6/ip6_input.c:76
NF_HOOK include/linux/netfilter.h:305 [inline]
NF_HOOK include/linux/netfilter.h:299 [inline]
ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:272
__netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4999
__netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5113
process_backlog+0x206/0x750 net/core/dev.c:5924
napi_poll net/core/dev.c:6347 [inline]
net_rx_action+0x508/0x10c0 net/core/dev.c:6413
__do_softirq+0x262/0x98c kernel/softirq.c:292
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1080
</IRQ>
do_softirq.part.0+0x11a/0x170 kernel/softirq.c:337
do_softirq kernel/softirq.c:329 [inline]
__local_bh_enable_ip+0x211/0x270 kernel/softirq.c:189
local_bh_enable include/linux/bottom_half.h:32 [inline]
inet_csk_listen_stop+0x1e0/0x850 net/ipv4/inet_connection_sock.c:993
tcp_close+0xd5b/0x10e0 net/ipv4/tcp.c:2338
inet_release+0xed/0x200 net/ipv4/af_inet.c:427
inet6_release+0x53/0x80 net/ipv6/af_inet6.c:470
__sock_release+0xce/0x280 net/socket.c:590
sock_close+0x1e/0x30 net/socket.c:1268
__fput+0x2ff/0x890 fs/file_table.c:280
____fput+0x16/0x20 fs/file_table.c:313
task_work_run+0x145/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x65f/0x760 arch/x86/entry/common.c:300
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x406571
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 24 1a 00 00 c3 48
83 ec 08 e8 6a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48
89 c2 e8 b3 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffc1a1a5e00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000406571
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000006dcc20 R08: 0000000000000140 R09: 0000000000000140
R10: 00007ffc1a1a5e30 R11: 0000000000000293 R12: 00007ffc1a1a5e60
R13: 00000000006dcc2c R14: 000000000000002d R15: 0000000000000007


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[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.