Re: linux-next: build failure after merge of the akpm-current tree

Randy Dunlap
2019-11-15T23:37:39Z

On 11/15/19 3:23 PM, Andrew Morton wrote:
> On Fri, 15 Nov 2019 18:19:57 +1100 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
>> Hi all,
>>
>> [Also reported by Randy Dunlap]
>>
>> After merging the akpm-current tree, today's linux-next build (arm
>> multi_v7_defconfig) failed like this:
>>
>> mm/vmalloc.c: In function '__purge_vmap_area_lazy':
>> mm/vmalloc.c:1286:8: error: 'SHARED_KERNEL_PMD' undeclared (first use in this function)
>> 1286 | if (!SHARED_KERNEL_PMD && boot_cpu_has(X86_FEATURE_PTI))
>> | ^~~~~~~~~~~~~~~~~
>> mm/vmalloc.c:1286:8: note: each undeclared identifier is reported only once for each function it appears in
>> mm/vmalloc.c:1286:29: error: implicit declaration of function 'boot_cpu_has' [-Werror=implicit-function-declaration]
>> 1286 | if (!SHARED_KERNEL_PMD && boot_cpu_has(X86_FEATURE_PTI))
>> | ^~~~~~~~~~~~
>> mm/vmalloc.c:1286:42: error: 'X86_FEATURE_PTI' undeclared (first use in this function)
>> 1286 | if (!SHARED_KERNEL_PMD && boot_cpu_has(X86_FEATURE_PTI))
>> | ^~~~~~~~~~~~~~~
>>
>> Caused by commit
>>
>> 07ef40e149bf ("mm-vmalloc-fix-regression-caused-by-needless-vmalloc_sync_all-fix")
>>
>> SHARED_KERNEL_PMD, boot_cpu_has() and X86_FEATURE_PTI are only defined
>> for X86.
>>
>> I have reverted that commit for today.
>
> Thanks. So it has to be an ifdef.

Yes, that works. Thanks.

Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested

> --- a/mm/vmalloc.c~mm-vmalloc-fix-regression-caused-by-needless-vmalloc_sync_all-fix-fix
> +++ a/mm/vmalloc.c
> @@ -1255,17 +1255,17 @@ static bool __purge_vmap_area_lazy(unsig
> if (unlikely(valist == NULL))
> return false;
>
> - if (IS_ENABLED(CONFIG_X86_PAE)) {
> - /*
> - * First make sure the mappings are removed from all page-tables
> - * before they are freed.
> - *
> - * This is only needed on x86-32 with !SHARED_KERNEL_PMD, which
> - * is the case on a PAE kernel with PTI enabled.
> - */
> - if (!SHARED_KERNEL_PMD && boot_cpu_has(X86_FEATURE_PTI))
> - vmalloc_sync_all();
> - }
> +#ifdef CONFIG_X86_PAE
> + /*
> + * First make sure the mappings are removed from all pagetables before
> + * they are freed.
> + *
> + * This is only needed on x86-32 with !SHARED_KERNEL_PMD, which is the
> + * case on a PAE kernel with PTI enabled.
> + */
> + if (!SHARED_KERNEL_PMD && boot_cpu_has(X86_FEATURE_PTI))
> + vmalloc_sync_all();
> +#endif
>
> /*
> * TODO: to calculate a flush range without looping.
> _
>

--
~Randy
Reported-by: Randy Dunlap <rdunlap@infradead.org>