INFO: rcu detected stall in unwind_next_frame

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 4b9c77680375 Merge branch 'sched-refactor-NOLOCK-qdiscs'
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14057397800000
kernel config: https://syzkaller.appspot.com/x/.config?x=b632d8e2c2ab2c1
dashboard link: https://syzkaller.appspot.com/bug?extid=bbcdb86f1e06dffe2b84
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [h...@zytor.com jpoi...@redhat.com
linux-...@vger.kernel.org mhir...@kernel.org mi...@redhat.com
tg...@linutronix.de x...@kernel.org]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+bbcdb8...@syzkaller.appspotmail.com

kernel msg: ebtables bug: please report to author: EBT_ENTRY_OR_ENTRIES
shouldn't be set in distinguisher
INFO: rcu_sched self-detected stall on CPU
0-...!: (120232 ticks this GP) idle=3da/1/4611686018427387906
softirq=85066/85067 fqs=87
(t=125000 jiffies g=45941 c=45940 q=632561)
rcu_sched kthread starved for 96651 jiffies! g45941 c45940 f0x2
RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1
RCU grace-period kthread stack dump:
rcu_sched R running task 22584 9 2 0x80000000
Call Trace:
context_switch kernel/sched/core.c:2848 [inline]
__schedule+0x801/0x1e30 kernel/sched/core.c:3490
schedule+0xef/0x430 kernel/sched/core.c:3549
schedule_timeout+0x138/0x240 kernel/time/timer.c:1801
rcu_gp_kthread+0x6b5/0x1940 kernel/rcu/tree.c:2231
kthread+0x345/0x410 kernel/kthread.c:238
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
NMI backtrace for cpu 0
CPU: 0 PID: 8 Comm: ksoftirqd/0 Not tainted 4.17.0-rc4+ #48
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+0x1b9/0x294 lib/dump_stack.c:113
nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x151/0x192 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:156 [inline]
rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376
print_cpu_stall kernel/rcu/tree.c:1525 [inline]
check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593
__rcu_pending kernel/rcu/tree.c:3356 [inline]
rcu_pending kernel/rcu/tree.c:3401 [inline]
rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763
update_process_times+0x2d/0x70 kernel/time/timer.c:1636
tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
__run_hrtimer kernel/time/hrtimer.c:1398 [inline]
__hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1460
hrtimer_interrupt+0x2f3/0x750 kernel/time/hrtimer.c:1518
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
</IRQ>
RIP: 0010:unwind_next_frame.part.7+0x8b/0x9c0
arch/x86/kernel/unwind_frame.c:291
RSP: 0018:ffff8801d9aaebb0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff1003b355da3 RBX: ffff8801d9aaecc8 RCX: 0000000000000007
RDX: dffffc0000000000 RSI: ffffffff86e8b04f RDI: ffff8801d9aaecc8
RBP: ffff8801d9aaeca0 R08: ffff8801d9aaed00 R09: ffff8801d9a9c200
R10: ffffed003b355da3 R11: ffff8801d9aaed1f R12: 1ffff1003b355d7b
R13: 0000000000000000 R14: ffff8801d9a9c200 R15: ffff8801d9aaed18
unwind_next_frame+0x3e/0x50 arch/x86/kernel/unwind_frame.c:287
__save_stack_trace+0x6e/0xd0 arch/x86/kernel/stacktrace.c:44
save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
kmem_cache_zalloc include/linux/slab.h:691 [inline]
sctp_chunkify+0xce/0x400 net/sctp/sm_make_chunk.c:1340
_sctp_make_chunk+0x157/0x280 net/sctp/sm_make_chunk.c:1413
sctp_make_control net/sctp/sm_make_chunk.c:1449 [inline]
sctp_make_heartbeat+0x8f/0x430 net/sctp/sm_make_chunk.c:1156
sctp_sf_heartbeat.isra.23+0x26/0x180 net/sctp/sm_statefuns.c:1005
sctp_sf_sendbeat_8_3+0x38e/0x550 net/sctp/sm_statefuns.c:1049
sctp_do_sm+0x1ab/0x7160 net/sctp/sm_sideeffect.c:1188
sctp_generate_heartbeat_event+0x218/0x450 net/sctp/sm_sideeffect.c:406
call_timer_fn+0x230/0x940 kernel/time/timer.c:1326
expire_timers kernel/time/timer.c:1363 [inline]
__run_timers+0x79e/0xc50 kernel/time/timer.c:1666
run_timer_softirq+0x4c/0x70 kernel/time/timer.c:1692
__do_softirq+0x2e0/0xaf5 kernel/softirq.c:285
run_ksoftirqd+0x86/0x100 kernel/softirq.c:646
smpboot_thread_fn+0x417/0x870 kernel/smpboot.c:164
kthread+0x345/0x410 kernel/kthread.c:238
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412


---
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[Dmitry Vyukov]

#syz fix: sctp: not allow to set rto_min with a value below 200 msecs

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