Greeting,

FYI, we noticed the following commit (built with gcc-7):

commit: fa6726c1e7f015bb77f07fc81c32a97b33e4f6c4 ("mm/debug: add tests validating architecture page table helpers")
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-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G

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


+-----------------------------------------------------------+------------+------------+
|                                                           | e3eec8dce1 | fa6726c1e7 |
+-----------------------------------------------------------+------------+------------+
| boot_successes                                            | 0          | 0          |
| boot_failures                                             | 16         | 20         |
| Kernel_panic-not_syncing:Attempted_to_kill_init!exitcode= | 12         |            |
| BUG:kernel_hang_in_test_stage                             | 4          |            |
| kernel_BUG_at_include/linux/mm.h                          | 0          | 20         |
| invalid_opcode:#[##]                                      | 0          | 20         |
| EIP:__free_pages                                          | 0          | 20         |
| Kernel_panic-not_syncing:Fatal_exception                  | 0          | 20         |
+-----------------------------------------------------------+------------+------------+


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


[   10.263354] kernel BUG at include/linux/mm.h:699!
[   10.264320] invalid opcode: 0000 [#1] SMP
[   10.264872] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc2-00230-gfa6726c1e7f01 #2
[   10.265928] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[   10.267074] EIP: __free_pages+0x4f/0x62
[   10.267615] Code: 85 ff 74 0e 89 fa 89 f0 e8 83 ed ff ff 5b 5e 5f 5d c3 89 f0 e8 57 ff ff ff 5b 5e 5f 5d c3 ba fc 86 fc c1 89 f0 e8 ff 2e fe ff <0f> 0b 0f b6 cb ba ff ff ff ff 89 f0 e8 07 8f 01 00 eb bf 55 89 e5
[   10.270098] EAX: 0000003e EBX: ee800000 ECX: 00000000 EDX: c0068000
[   10.270925] ESI: eece0640 EDI: c016d020 EBP: c0071f10 ESP: c0071f04
[   10.271786] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010286
[   10.272724] CR0: 80050033 CR2: b7d6467d CR3: 023d0000 CR4: 000006b0
[   10.273572] Call Trace:
[   10.273912]  free_pages+0x3d/0x43
[   10.274367]  pgd_free+0xea/0x11b
[   10.274807]  __mmdrop+0x3c/0xc7
[   10.275237]  ? __free_pages+0x3e/0x62
[   10.275761]  debug_vm_pgtable+0x411/0x419
[   10.276305]  ? rest_init+0x23c/0x23c
[   10.276767]  kernel_init+0x15/0xf4
[   10.277208]  ? schedule_tail_wrapper+0x9/0xc
[   10.277756]  ret_from_fork+0x2e/0x38
[   10.278217] Modules linked in: stm_p_basic
[   10.278776] ---[ end trace b838f89424113a3a ]---


To reproduce:

        # build kernel
	cd linux
	cp config-5.7.0-rc2-00230-gfa6726c1e7f01 .config
	make HOSTCC=gcc-7 CC=gcc-7 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