Greeting,

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

commit: 98e158f6a8387ec8f0487d6068d90f652105d38b ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master


in testcase: boot

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):


+---------------------------------------------+------------+------------+
|                                             | 87f2e7827e | 98e158f6a8 |
+---------------------------------------------+------------+------------+
| boot_successes                              | 8          | 0          |
| boot_failures                               | 0          | 8          |
| BUG:unable_to_handle_page_fault_for_address | 0          | 8          |
| Oops:#[##]                                  | 0          | 8          |
| EIP:hugetlb_advanced_tests                  | 0          | 8          |
| Kernel_panic-not_syncing:Fatal_exception    | 0          | 8          |
+---------------------------------------------+------------+------------+


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


[   12.197509] BUG: unable to handle page fault for address: 027f6000
[   12.199044] #PF: supervisor read access in kernel mode
[   12.200462] #PF: error_code(0x0000) - not-present page
[   12.202043] *pde = 00000000 
[   12.203200] Oops: 0000 [#1] PREEMPT SMP
[   12.204556] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc4-00052-g98e158f6a8387 #1
[   12.207158] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[   12.210066] EIP: hugetlb_advanced_tests+0x3e/0x242
[   12.211667] Code: 45 0c 89 45 ec 89 c8 c1 e8 0e 8b 04 c5 80 ae f6 dd 6b c9 28 83 e0 f0 8d 3c 08 8b 02 a1 78 b0 f6 dd 83 e0 f0 8d b0 00 60 7f 02 <8b> 80 00 60 7f 02 c1 e8 1a 8b 04 c5 80 ae f6 dd 83 e0 f0 29 c6 8b
[   12.217108] EAX: 00000000 EBX: f2651ff8 ECX: 004a88a0 EDX: f2651ff8
[   12.218932] ESI: 027f6000 EDI: f4a088a0 EBP: f42d5eb4 ESP: f42d5e94
[   12.220765] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010246
[   12.222701] CR0: 80050033 CR2: 027f6000 CR3: 1de2b000 CR4: 00040690
[   12.224480] Call Trace:
[   12.225615]  ? preempt_count_add+0x125/0x140
[   12.227167]  ? debug_vm_pgtable+0x2eb/0x73e
[   12.228689]  debug_vm_pgtable+0x503/0x73e
[   12.230169]  ? hugetlb_advanced_tests+0x242/0x242
[   12.231828]  do_one_initcall+0x3f/0x2d0
[   12.233156]  ? __might_sleep+0x106/0x120
[   12.234503]  ? rdinit_setup+0x2a/0x2a
[   12.235816]  do_initcalls+0xae/0xd1
[   12.237319]  kernel_init_freeable+0x101/0x149
[   12.241622]  ? rest_init+0xb2/0xb2
[   12.242801]  kernel_init+0xd/0xee
[   12.243999]  ret_from_fork+0x19/0x24
[   12.245283] Modules linked in:
[   12.246480] CR2: 00000000027f6000
[   12.247735] ---[ end trace d710d4452b628192 ]---


To reproduce:

        # build kernel
	cd linux
	cp config-5.8.0-rc4-00052-g98e158f6a8387 .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