Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 8e4ec3d02b549a731c94b4bcddff212bb92cdbaf ("refperf: Rename RCU_REF_PERF_TEST to RCU_REF_SCALE_TEST")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master

in testcase: trinity
with following parameters:

	runtime: 300s

test-description: Trinity is a linux system call fuzz tester.
test-url: http://codemonkey.org.uk/projects/trinity/


on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+---------------------------------------------------------+------------+------------+
|                                                         | c7dcf8106f | 8e4ec3d02b |
+---------------------------------------------------------+------------+------------+
| boot_successes                                          | 14         | 0          |
| boot_failures                                           | 23         | 38         |
| invoked_oom-killer:gfp_mask=0x                          | 5          | 4          |
| Mem-Info                                                | 5          | 4          |
| Out_of_memory_and_no_killable_processes                 | 4          | 4          |
| Kernel_panic-not_syncing:System_is_deadlocked_on_memory | 4          | 4          |
| WARNING:at_kernel/trace/trace.c:#trace_find_next_entry  | 18         |            |
| EIP:trace_find_next_entry                               | 18         |            |
| error:#[##]                                             | 0          | 34         |
| EIP:main_func                                           | 0          | 34         |
| Kernel_panic-not_syncing:Fatal_exception                | 0          | 34         |
+---------------------------------------------------------+------------+------------+


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <lkp@intel.com>


[   14.325320] 
[   14.337793] [main] Added 18 filenames from /dev
[   14.337808] 
[   15.232694] rcu-ref-perf: Experiment #0 (Format: <THREAD-NUM>:<Total loop time in ns>)
[   15.232694] 
[   15.238007] divide_error: 0000 [#1] PTI
[   15.239505] CPU: 0 PID: 86 Comm: main_func Tainted: G S                5.8.0-rc3-00028-g8e4ec3d02b549 #1
[   15.242735] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[   15.249804] EIP: main_func+0x2af/0x393
[   15.251276] Code: af f0 e8 86 f8 ff ff bf e8 03 00 00 69 ca e8 03 00 00 f7 e7 89 55 8c 89 45 88 8b 45 8c 31 ff 8d 14 01 39 d6 77 08 89 d0 31 d2 <f7> f6 89 c7 8b 4d 94 8b 45 88 f7 f6 89 7c d9 04 89 04 d9 43 e9 09
[   15.256851] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000000
[   15.258817] ESI: 00000000 EDI: 00000000 EBP: dc6cdf80 ESP: dc6cdf08
[   15.260738] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 EFLAGS: 00010246
[   15.262810] CR0: 80050033 CR2: 08bb0000 CR3: 33bbe000 CR4: 000406f0
[   15.264757] Call Trace:
[   15.265997]  ? __kthread_parkme+0x3a/0x71
[   15.267516]  ? _raw_spin_unlock_irqrestore+0x34/0x40
[   15.269216]  ? tracer_hardirqs_on+0x11/0x25
[   15.270767]  ? trace_hardirqs_on+0x34/0x41
[   15.272295]  kthread+0xee/0xf3
[   15.273636]  ? srcu_ref_perf_read_section+0x69/0x69
[   15.275325]  ? kthread_create_worker_on_cpu+0x1c/0x1c
[   15.277009]  ret_from_fork+0x19/0x30
[   15.278462] Modules linked in: psmouse parport_pc ide_pci_generic qemu_fw_cfg ide_core processor
[   15.281552] ---[ end trace 891088ef0ed36b53 ]---
[   15.283184] EIP: main_func+0x2af/0x393
[   15.284632] Code: af f0 e8 86 f8 ff ff bf e8 03 00 00 69 ca e8 03 00 00 f7 e7 89 55 8c 89 45 88 8b 45 8c 31 ff 8d 14 01 39 d6 77 08 89 d0 31 d2 <f7> f6 89 c7 8b 4d 94 8b 45 88 f7 f6 89 7c d9 04 89 04 d9 43 e9 09
[   15.290313] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000000
[   15.292272] ESI: 00000000 EDI: 00000000 EBP: dc6cdf80 ESP: dc6cdf08
[   15.294261] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 EFLAGS: 00010246
[   15.296304] CR0: 80050033 CR2: 08bb0000 CR3: 33bbe000 CR4: 000406f0
[   15.298264] Kernel panic - not syncing: Fatal exception
[   15.300001] Kernel Offset: disabled

Elapsed time: 60

qemu-img create -f qcow2 disk-vm-snb-i386-61-0 256G


To reproduce:

        # build kernel
	cd linux
	cp config-5.8.0-rc3-00028-g8e4ec3d02b549 .config
	make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 olddefconfig prepare modules_prepare bzImage

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
lkp