Re: [mm/debug] f8bf55f05f: BUG:non-zero_pgtables_bytes_on_freeing_mm

[Anshuman Khandual]

On 03/28/2020 06:37 PM, kernel test robot wrote:
> [    9.304270] debug_vm_pgtable: debug_vm_pgtable: Validating architecture page table helpers
> [    9.306147] random: get_random_u32 called from debug_vm_pgtable+0x2c/0x6a5 with crng_init=1
> [    9.306206] BUG: non-zero pgtables_bytes on freeing mm: -4096

This problem is on i386 platform via CONFIG_EXPERT with CONFIG_X86_PAE
still enabled. This particular configuration is not supported (even if
it could be tested via CONFIG_EXPERT) with ARCH_HAS_DEBUG_VM_PGTABLE.

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index beea77046f9b..df8a19e52e82 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -61,6 +61,7 @@  config X86
 	select ARCH_CLOCKSOURCE_INIT
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
 	select ARCH_HAS_DEBUG_VIRTUAL
+	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FAST_MULTIPLIER