Re: [PATCH 0/5] mm: poison critical mm/ structs

[Andrew Morton]

On Mon, 29 Sep 2014 21:47:14 -0400 Sasha Levin <sasha.levin@xxxxxxxxxx> wrote:

> Currently we're seeing a few issues which are unexplainable by looking at the
> data we see and are most likely caused by a memory corruption caused
> elsewhere.
> 
> This is wasting time for folks who are trying to figure out an issue provided
> a stack trace that can't really point out the real issue.
> 
> This patch introduces poisoning on struct page, vm_area_struct, and mm_struct,
> and places checks in busy paths to catch corruption early.
> 
> This series was tested, and it detects corruption in vm_area_struct. Right now
> I'm working on figuring out the source of the corruption, (which is a long
> standing bug) using KASan, but the current code is useful as it is.

Is this still useful if/when kasan is in place?

It looks fairly cheap - I wonder if it should simply fall under
CONFIG_DEBUG_VM rather than the new CONFIG_DEBUG_VM_POISON.

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