Re: 1808d65b55 ("asm-generic/tlb: Remove arch_tlb*_mmu()"): BUG: KASAN: stack-out-of-bounds in __change_page_attr_set_clr

David Howells
2019-04-12T16:50:30Z

Linus Torvalds <torvalds@linux-foundation.org> wrote:

> We should never have stack alignment bigger than 16 bytes. And
> preferably not even that.

At least one arch I know of (FRV) had instructions that could atomically
load/store register pairs or register quads, but they had to be pair- or
quad-aligned (ie. 8- or 16-byte), which made for more efficient code if you
could use them.

I don't know whether any arch we currently support has features like this (I
know some have multi-reg load/stores, but they seem to require only
word-alignment).

David