Re: [PATCH] arm64: fix warning about swapper_pg_dir overflow

From: Will Deacon
Date: Wed Feb 15 2017 - 06:34:04 EST


On Tue, Feb 14, 2017 at 10:27:01PM +0100, Arnd Bergmann wrote:
> With 4 levels of 16KB pages, we get this warning about the fact that we are
> copying a whole page into an array that is declared as having only two pointers
> for the top level of the page table:
>
> arch/arm64/mm/mmu.c: In function 'paging_init':
> arch/arm64/mm/mmu.c:528:2: error: 'memcpy' writing 16384 bytes into a region of size 16 overflows the destination [-Werror=stringop-overflow=]
>
> This is harmless since we actually reserve a whole page in the definition of the
> array that comes from, and just the extern declaration is short. The pgdir
> is initialized to zero either way, so copying the actual entries here seems
> like the best solution.

Thanks, I'll queue this up for 4.11 with the acks.

Will