INFO: rcu detected stall in kmem_cache_free

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syzbot

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Mar 25, 2020, 2:32:14 AM3/25/20
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Hello,

syzbot found the following crash on:

HEAD commit: 14cfdbd3 Linux 4.19.112
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15ca6a4be00000
kernel config: https://syzkaller.appspot.com/x/.config?x=48ea0e0a21a4900f
dashboard link: https://syzkaller.appspot.com/bug?extid=5f680beef8de65f2c227
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+5f680b...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-....: (1 GPs behind) idle=2e6/1/0x4000000000000004 softirq=137261/137262 fqs=5192
rcu: (t=10500 jiffies g=158769 q=145544)
NMI backtrace for cpu 0
CPU: 0 PID: 29744 Comm: syz-executor.3 Not tainted 4.19.112-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+0x188/0x20d lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
rcu_dump_cpu_stacks+0x170/0x1bb 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+0x634/0xddc kernel/rcu/tree.c:2682
update_process_times+0x2a/0x70 kernel/time/timer.c:1638
tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:168
tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1278
__run_hrtimer kernel/time/hrtimer.c:1401 [inline]
__hrtimer_run_queues+0x2fc/0xd50 kernel/time/hrtimer.c:1463
hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1521
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1092
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
RIP: 0010:trace_kmem_cache_free include/trace/events/kmem.h:144 [inline]
RIP: 0010:kmem_cache_free+0x198/0x260 mm/slab.c:3768
Code: ff e8 60 2b 63 ff e9 3a ff ff ff 48 63 75 74 48 89 df e8 cb b4 b8 01 e9 e2 fe ff ff 65 ff 05 1f b7 64 7e 48 8b 05 10 db e9 07 <e8> 93 23 b8 ff 85 c0 74 09 80 3d e0 65 e9 07 00 74 69 65 ff 0d ff
RSP: 0018:ffff8880ae607df0 EFLAGS: 00000207 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff888078880080 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff888054bdcd00 RDI: 0000000000000286
RBP: ffff88812c290080 R08: ffff888054bdc480 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8156504d
R13: ffffffff8156504d R14: ffff8880ae607e90 R15: dffffc0000000000
__rcu_reclaim kernel/rcu/rcu.h:236 [inline]
rcu_do_batch kernel/rcu/tree.c:2584 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
__rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
rcu_process_callbacks+0xb2d/0x17f0 kernel/rcu/tree.c:2881
__do_softirq+0x26c/0x93c kernel/softirq.c:292
invoke_softirq kernel/softirq.c:372 [inline]
irq_exit+0x17b/0x1c0 kernel/softirq.c:412
exiting_irq arch/x86/include/asm/apic.h:544 [inline]
smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1094
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
</IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 kernel/locking/spinlock.c:192
Code: c0 98 56 b2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d 81 31 93 01 00 74 25 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 e6 75 27 fa 65 8b 05 9f c8 e2 78 85 c0 74 02 5d
RSP: 0018:ffff88804f3a74a8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff1164ad3 RBX: ffff888054bdc480 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff888054bdccfc
RBP: ffff8880ae62c280 R08: ffff888054bdc480 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ae62c280
R13: ffff8880a91b4100 R14: ffff88809b6a8180 R15: 0000000000000402
finish_lock_switch kernel/sched/core.c:2576 [inline]
finish_task_switch+0x146/0x780 kernel/sched/core.c:2676
context_switch kernel/sched/core.c:2829 [inline]
__schedule+0x86e/0x1d80 kernel/sched/core.c:3515
preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:3742
retint_kernel+0x1b/0x2d
RIP: 0010:__sanitizer_cov_trace_pc+0x22/0x50 kernel/kcov.c:101
Code: 00 00 e9 24 ec ff ff 90 48 8b 34 24 65 48 8b 04 25 40 ee 01 00 65 8b 15 fc 48 9a 7e 81 e2 00 01 1f 00 75 2b 8b 90 d0 12 00 00 <83> fa 02 75 20 48 8b 88 d8 12 00 00 8b 80 d4 12 00 00 48 8b 11 48
RSP: 0018:ffff88804f3a76c8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff888054bdc480 RBX: dffffc0000000000 RCX: ffffffff8196b6fb
RDX: 0000000000000000 RSI: ffffffff8196b714 RDI: ffffea0002804c00
RBP: ffffea0002804c00 R08: ffff888054bdc480 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0002804c00
R13: ffff88808f1e00e8 R14: 000000000000001b R15: 00000000000001fe
constant_test_bit arch/x86/include/asm/bitops.h:317 [inline]
PageSwapBacked include/linux/page-flags.h:295 [inline]
PageSwapCache include/linux/page-flags.h:340 [inline]
free_swap_cache mm/swap_state.c:290 [inline]
free_pages_and_swap_cache+0x174/0x3e0 mm/swap_state.c:318
tlb_flush_mmu_free+0x72/0x140 mm/memory.c:249
zap_pte_range mm/memory.c:1405 [inline]
zap_pmd_range mm/memory.c:1440 [inline]
zap_pud_range mm/memory.c:1469 [inline]
zap_p4d_range mm/memory.c:1490 [inline]
unmap_page_range+0x171b/0x1de0 mm/memory.c:1511
unmap_single_vma+0x196/0x300 mm/memory.c:1556
unmap_vmas+0xa9/0x180 mm/memory.c:1586
exit_mmap+0x2b2/0x510 mm/mmap.c:3091
__mmput kernel/fork.c:1015 [inline]
mmput+0x14e/0x4a0 kernel/fork.c:1036
exit_mm kernel/exit.c:546 [inline]
do_exit+0xac8/0x2f30 kernel/exit.c:867
do_group_exit+0x125/0x350 kernel/exit.c:983
get_signal+0x3ec/0x1f90 kernel/signal.c:2588
do_signal+0x8f/0x1710 arch/x86/kernel/signal.c:821
exit_to_usermode_loop+0x22b/0x2b0 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+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c849
Code: Bad RIP value.
RSP: 002b:00007fc4101c3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: fffffffffffffff5 RBX: 00007fc4101c46d4 RCX: 000000000045c849
RDX: 0000000000000048 RSI: 00000000200054c0 RDI: 0000000000000005
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000068 R14: 00000000004c3099 R15: 000000000076bf0c


---
This bug is generated by a bot. It may contain errors.
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syzbot

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Jul 30, 2020, 2:56:17 PM7/30/20
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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