INFO: rcu detected stall in mrp_periodic_timer

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b499cf4b Linux 4.19.102
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10e582e6e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=7ebf58b0a913d3ef
dashboard link: https://syzkaller.appspot.com/bug?extid=2432000ea696e55b527e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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+243200...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_UP): veth1707: link is not ready
IPv6: ADDRCONF(NETDEV_UP): vlan719: link is not ready
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (10499 ticks this GP) idle=f66/1/0x4000000000000004 softirq=316579/316579 fqs=10
rcu: (t=10501 jiffies g=350809 q=362)
rcu: rcu_preempt kthread starved for 10482 jiffies! g350809 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt R running task 29104 10 2 0x80000000
Call Trace:
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x866/0x1dc0 kernel/sched/core.c:3515
schedule+0x92/0x1c0 kernel/sched/core.c:3559
schedule_timeout+0x4db/0xfc0 kernel/time/timer.c:1806
rcu_gp_kthread+0xd5c/0x2190 kernel/rcu/tree.c:2202
kthread+0x354/0x420 kernel/kthread.c:246
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
NMI backtrace for cpu 0
CPU: 0 PID: 12765 Comm: syz-executor.4 Not tainted 4.19.102-syzkaller #0
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+0x197/0x210 lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 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+0x189/0x1d5 kernel/rcu/tree.c:1340
print_cpu_stall kernel/rcu/tree.c:1478 [inline]
check_cpu_stall kernel/rcu/tree.c:1550 [inline]
__rcu_pending kernel/rcu/tree.c:3293 [inline]
rcu_pending kernel/rcu/tree.c:3336 [inline]
rcu_check_callbacks.cold+0x5e3/0xd90 kernel/rcu/tree.c:2682
update_process_times+0x32/0x80 kernel/time/timer.c:1638
tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:168
tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1278
__run_hrtimer kernel/time/hrtimer.c:1401 [inline]
__hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1463
hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1521
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1092
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
RIP: 0010:mrp_periodic_timer+0x46/0x50 net/802/mrp.c:618
Code: e8 1f 36 7c 01 be 0c 00 00 00 4c 89 ef e8 f2 fe ff ff 4c 89 ef e8 5a de ff ff 4c 89 e7 e8 22 38 7c 01 4c 89 ef e8 1a d1 ff ff <41> 5c 41 5d 5d c3 0f 1f 40 00 55 48 89 e5 41 57 41 56 41 55 49 89
RSP: 0018:ffff8880ae807cf8 EFLAGS: 00000292 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff888097a2fa58 RCX: 1ffff11015d00f88
RDX: 0000000000000100 RSI: ffffffff815ba6e6 RDI: 0000000000000001
RBP: ffff8880ae807d08 R08: ffff888010a564c0 R09: ffff888010a56d88
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888097a2faa0
R13: ffff888097a2fa00 R14: 1ffff11015d00fa6 R15: 0000000000000000
call_timer_fn+0x18d/0x720 kernel/time/timer.c:1326
expire_timers kernel/time/timer.c:1363 [inline]
__run_timers kernel/time/timer.c:1684 [inline]
__run_timers kernel/time/timer.c:1652 [inline]
run_timer_softirq+0x64f/0x16a0 kernel/time/timer.c:1697
__do_softirq+0x25c/0x921 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:372 [inline]
irq_exit+0x180/0x1d0 kernel/softirq.c:412
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1094
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
</IRQ>
RIP: 0010:zap_pte_range mm/memory.c:1323 [inline]
RIP: 0010:zap_pmd_range mm/memory.c:1440 [inline]
RIP: 0010:zap_pud_range mm/memory.c:1469 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:1490 [inline]
RIP: 0010:unmap_page_range+0x9c9/0x1fb0 mm/memory.c:1511
Code: 20 ff ff ff 00 49 89 c7 0f 85 02 0f 00 00 e8 8e c9 d5 ff 48 8b 85 50 ff ff ff 48 8d 78 20 48 89 f8 48 c1 e8 03 42 0f b6 04 20 <84> c0 74 06 0f 8e 5a 13 00 00 48 8b 85 50 ff ff ff 31 ff 0f b6 40
RSP: 0018:ffff88800bf3f708 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: 00007fe4a9fa2000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff819541f2 RDI: ffff88800bf3f968
RBP: ffff88800bf3f868 R08: ffff888010a564c0 R09: fffff940003fbb87
R10: fffff940003fbb86 R11: ffffea0001fddc33 R12: dffffc0000000000
R13: 0000000000000001 R14: 800000007f771007 R15: ffffea0001fddc40
unmap_single_vma+0x19d/0x300 mm/memory.c:1556
unmap_vmas+0xae/0x180 mm/memory.c:1586
exit_mmap+0x2c2/0x530 mm/mmap.c:3091
__mmput kernel/fork.c:1015 [inline]
mmput+0x15f/0x4c0 kernel/fork.c:1036
exit_mm kernel/exit.c:546 [inline]
do_exit+0xb1e/0x30d0 kernel/exit.c:867
do_group_exit+0x135/0x370 kernel/exit.c:983
get_signal+0x3ec/0x1fc0 kernel/signal.c:2583
do_signal+0x95/0x1960 arch/x86/kernel/signal.c:821
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x53d/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b399
Code: Bad RIP value.
RSP: 002b:00007fe4a955bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: 0000000000000005 RBX: 00007fe4a955c6d4 RCX: 000000000045b399
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000b4d R14: 00000000004cc390 R15: 000000000075bf2c


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.