INFO: rcu detected stall in mrp_periodic_timer

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 8bac5040 Linux 4.14.167
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=130a4769e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ffa08bc186ce2d1
dashboard link: https://syzkaller.appspot.com/bug?extid=87f99ce190f683d48487
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+87f99c...@syzkaller.appspotmail.com

INFO: rcu_sched detected stalls on CPUs/tasks:
(detected by 0, t=10502 jiffies, g=32824, c=32823, q=4)
All QSes seen, last rcu_sched kthread activity 10502 (4295038179-4295027677), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.3 R running task 28240 14581 7366 0x8000000c
Call Trace:
<IRQ>
sched_show_task kernel/sched/core.c:5168 [inline]
sched_show_task.cold+0x2f0/0x351 kernel/sched/core.c:5143
print_other_cpu_stall kernel/rcu/tree.c:1501 [inline]
check_cpu_stall kernel/rcu/tree.c:1616 [inline]
__rcu_pending kernel/rcu/tree.c:3390 [inline]
rcu_pending kernel/rcu/tree.c:3452 [inline]
rcu_check_callbacks.cold+0xcb1/0xd0a kernel/rcu/tree.c:2792
update_process_times+0x31/0x70 kernel/time/timer.c:1590
tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:165
tick_sched_timer+0x43/0x130 kernel/time/tick-sched.c:1223
__run_hrtimer kernel/time/hrtimer.c:1223 [inline]
__hrtimer_run_queues+0x270/0xbc0 kernel/time/hrtimer.c:1287
hrtimer_interrupt+0x1d8/0x5d0 kernel/time/hrtimer.c:1321
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
smp_apic_timer_interrupt+0x11c/0x5e0 arch/x86/kernel/apic/apic.c:1100
apic_timer_interrupt+0x96/0xa0 arch/x86/entry/entry_64.S:792
RIP: 0010:mrp_periodic_timer+0x4/0x50 net/802/mrp.c:609
RSP: 0018:ffff8880aec07d40 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff10
RAX: ffffffff852d4d00 RBX: ffff88809f0435e0 RCX: ffff888067f4ae80
RDX: 0000000000000100 RSI: ffffffff87f87220 RDI: ffff88809f043580
RBP: ffff8880aec07d40 R08: 0000000000007759 R09: ffffffff895a4488
R10: ffff888067f4aed0 R11: ffff888067f4a600 R12: 0000000000000101
R13: ffff8880aec07dd0 R14: ffff8880aec239c0 R15: 0000000000000000
call_timer_fn+0x161/0x670 kernel/time/timer.c:1279
expire_timers kernel/time/timer.c:1318 [inline]
__run_timers kernel/time/timer.c:1636 [inline]
__run_timers kernel/time/timer.c:1604 [inline]
run_timer_softirq+0x5b7/0x1520 kernel/time/timer.c:1649
__do_softirq+0x244/0x9a0 kernel/softirq.c:288
invoke_softirq kernel/softirq.c:368 [inline]
irq_exit+0x160/0x1b0 kernel/softirq.c:409
exiting_irq arch/x86/include/asm/apic.h:648 [inline]
smp_apic_timer_interrupt+0x146/0x5e0 arch/x86/kernel/apic/apic.c:1102
apic_timer_interrupt+0x96/0xa0 arch/x86/entry/entry_64.S:792
</IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x60 kernel/kcov.c:68
RSP: 0018:ffff88820c887770 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
RAX: ffff888067f4a600 RBX: 0000000000000000 RCX: 1ffffffff0f82dac
RDX: 0000000000000000 RSI: ffffffff87047cc0 RDI: ffffea0002208f40
RBP: ffff88820c8877a8 R08: 0000000000000000 R09: ffff888067f4aec8
R10: ffff888067f4aea8 R11: ffff888067f4a600 R12: ffffea0002208f40
R13: ffffea0002208f60 R14: ffffea0002208f40 R15: dead000000000100
zap_pte_range mm/memory.c:1342 [inline]
zap_pmd_range mm/memory.c:1444 [inline]
zap_pud_range mm/memory.c:1473 [inline]
zap_p4d_range mm/memory.c:1494 [inline]
unmap_page_range+0xabd/0x19f0 mm/memory.c:1515
unmap_single_vma+0x15d/0x2c0 mm/memory.c:1560
unmap_vmas+0xac/0x170 mm/memory.c:1590
exit_mmap+0x285/0x4e0 mm/mmap.c:3056
__mmput kernel/fork.c:930 [inline]
mmput+0x114/0x440 kernel/fork.c:951
exit_mm kernel/exit.c:545 [inline]
do_exit+0x952/0x2cd0 kernel/exit.c:845
do_group_exit+0x111/0x330 kernel/exit.c:955
get_signal+0x381/0x1cd0 kernel/signal.c:2413
do_signal+0x86/0x19a0 arch/x86/kernel/signal.c:814
exit_to_usermode_loop+0x15c/0x220 arch/x86/entry/common.c:160
prepare_exit_to_usermode+0x1b5/0x220 arch/x86/entry/common.c:199
retint_user+0x8/0x18
RIP: 0033:0x45e18a
RSP: 002b:00007f35f4944c58 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000000 RBX: 000000000075bf28 RCX: 000000000045e18a
RDX: 0000000000000000 RSI: 00007f35f4944c60 RDI: 0000000000000001
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c
R13: 0000000000000b38 R14: 00000000004cc22c 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.