preemptirq_delay_test module can trigger crash on arm64 vm

From: Xiao Yang <yangx.jy@cn.fujitsu.com>
To: Steven Rostedt <rostedt@goodmis.org>, <joel@joelfernandes.org>
Cc: <linux-kselftest@vger.kernel.org>,
	<linux-trace-devel@vger.kernel.org>,
	Xiao Yang <ice_yangxiao@163.com>
Subject: preemptirq_delay_test module can trigger crash on arm64 vm
Date: Fri, 24 Apr 2020 17:26:32 +0800	[thread overview]
Message-ID: <5EA2B0C8.2080706@cn.fujitsu.com> (raw)

Hi Steve, Joel

Sorry to bother you.

On my slow arm64 vm, inserting and removing preemptirq_delay_test module
in loops triggers kernel panic sometimes.

Reproduce steps:
Do the following steps in loops(more than 10 times):
[root@CentOS81-aarch64 ]# modprobe preemptirq_delay_test
test_mode=preempt delay=500000; rmmod preemptirq_delay_test

Call Trace:
-------------------------------------------------------------------
[172413.750294] Unable to handle kernel paging request at virtual
address fffffe0009010280
[172413.790511] Mem abort info:
[172413.791129]   ESR = 0x86000007
[172413.791656]   EC = 0x21: IABT (current EL), IL = 32 bits
[172413.792322]   SET = 0, FnV = 0
[172413.792793]   EA = 0, S1PTW = 0
[172413.794082] swapper pgtable: 64k pages, 42-bit VAs,
pgdp=0000000040ef0000
[172413.794556] [fffffe0009010280] pgd=00000000bfff0003,
pud=00000000bfff0003, pmd=00000000bfff0003, pte=0000000000000000
[172413.795690] Internal error: Oops: 86000007 [#1] PREEMPT SMP
[172413.796285] Modules linked in: sunrpc vfat fat ext4 mbcache jbd2
crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce ip_tables xfs
libcrc32c virtio_net net_failover failover virtio_blk virtio_mmio [last
unloaded: preemptirq_delay_test]
[172413.797797] CPU: 1 PID: 15750 Comm: preempt_test Not tainted
5.6.0-rc7 #17
[172413.798275] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0
02/06/2015
[172413.799049] pstate: 40000005 (nZcv daif -PAN -UAO)
[172413.799934] pc : 0xfffffe0009010280
[172413.800230] lr : 0xfffffe0009010280
[172413.800497] sp : fffffe001390fe00
[172413.800799] x29: fffffe001390fe00 x28: 0000000000000000
[172413.801263] x27: 0000000000000000 x26: fffffe0009010000
[172413.801726] x25: 0000000000000000 x24: fffffe00114a3670
[172413.802164] x23: fffffe0010d1d150 x22: fffffe0016b2f9e8
[172413.802635] x21: 0000000000000000 x20: fffffe0009030008
[172413.803191] x19: fffffe0009030000 x18: 0000000000000000
[172413.803672] x17: 0000000000000000 x16: 0000000000000000
[172413.804118] x15: 0000000000000000 x14: 0000000000000000
[172413.804558] x13: 0000000000000000 x12: 0000000000000000
[172413.805013] x11: 0000000000000000 x10: 0000000000000d50
[172413.805441] x9 : fffffe001390fd10 x8 : fffffc00762930b0
[172413.805944] x7 : 00000000fa83b2da x6 : 0000000000000000
[172413.806455] x5 : fffffe001127c000 x4 : fffffe006ed00000
[172413.806874] x3 : fffffe001127cf50 x2 : 0000000000000002
[172413.807312] x1 : 0000000000000000 x0 : 0000000000000228
[172413.807869] Call trace:
[172413.808146]  0xfffffe0009010280
[172413.808436]  0xfffffe0009010294
[172413.808723]  0xfffffe0009010050
[172413.809519]  kthread+0x110/0x118
[172413.809734]  ret_from_fork+0x10/0x18
[172413.810338] Code: bad PC value
[172413.811203] ---[ end trace 69c688402fdc8bb1 ]---
[172413.811670] Kernel panic - not syncing: Fatal exception
[172413.812108] SMP: stopping secondary CPUs
[172413.812733] Kernel Offset: disabled
[172413.813043] CPU features: 0x10002,20006082
[172413.813387] Memory Limit: none
[172413.813849] ---[ end Kernel panic - not syncing: Fatal exception]---
-------------------------------------------------------------------

Do you have any suggestion about the issue.

Thanks,
Xiao Yang