Subject: [mm/debug] d157503f6f: WARNING:at_mm/debug_vm_pgtable.c:#debug_vm_pgtable

From: kernel test robot <[email-masked]>
Date: Fri, 27 Mar 2020 15:41:01 +0800

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

commit: d157503f6ff935d0ab4e0c3f324099a458597b5d ("[PATCH V2 2/3] mm/debug: Add tests validating arch advanced page table helpers")
url: https://github.com/0day-ci/linux/commits/Anshuman-Khandual/mm-debug-Add-more-arch-page-table-helper-tests/20200324-161233

in testcase: boot

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):

+-----------------------------------------------------------+------------+------------+
|                                                           | f675f2f91d | d157503f6f |
+-----------------------------------------------------------+------------+------------+
| boot_successes                                            | 0          | 0          |
| boot_failures                                             | 4          | 4          |
| Kernel_panic-not_syncing:Attempted_to_kill_init!exitcode= | 4          | 4          |
| WARNING:at_mm/debug_vm_pgtable.c:#debug_vm_pgtable        | 0          | 4          |
| EIP:debug_vm_pgtable                                      | 0          | 4          |
+-----------------------------------------------------------+------------+------------+

If you fix the issue, kindly add following tag
Reported-by: kernel test robot <[email-masked]>

[   25.884391] WARNING: CPU: 0 PID: 1 at mm/debug_vm_pgtable.c:203 debug_vm_pgtable+0x320/0x51a
[   25.886281] Modules linked in:
[   25.886838] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc7-next-20200323-00002-gd157503f6ff93 #1
[   25.888378] EIP: debug_vm_pgtable+0x320/0x51a
[   25.889113] Code: 00 00 00 83 f8 01 19 c0 25 00 f0 3f 00 2d 00 00 40 00 f7 d0 21 d0 a8 20 74 02 0f 0b 8b 45 f0 e8 3b ff 31 fe c7 03 00 00 00 00 <0f> 0b 0f 0b 8b 03 85 c0 74 02 0f 0b 8b 45 f0 e8 21 ff 31 fe 8b 45
[   25.892453] EAX: 00000025 EBX: e9160444 ECX: e9160444 EDX: 00000000
[   25.893652] ESI: 44800000 EDI: 16800080 EBP: c0265fa4 ESP: c0265f7c
[   25.894842] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010246
[   25.900205] CR0: 80050033 CR2: b7d17b20 CR3: 16ae4000 CR4: 000006d0
[   25.901289] Call Trace:
[   25.901728]  ? rest_init+0x110/0x110
[   25.902395]  kernel_init+0x12/0x110
[   25.903065]  ret_from_fork+0x2e/0x40
[   25.903797] ---[ end trace a6228a4356840124 ]---

To reproduce:

        # build kernel
	cd linux
	cp config-5.6.0-rc7-next-20200323-00002-gd157503f6ff93 .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,
Rong Chen