Re: [PATCH v6 1/1] mm/memory-failure: disable unpoison once hw error happens

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 15 Jun 2022 10:34:06 +0000 HORIGUCHI NAOYA(堀口　直也) <naoya.horiguchi@nec.com> wrote:

> On Wed, Jun 15, 2022 at 05:32:09PM +0800, zhenwei pi wrote:
> > Currently unpoison_memory(unsigned long pfn) is designed for soft
> > poison(hwpoison-inject) only. Since 17fae1294ad9d, the KPTE gets
> > cleared on a x86 platform once hardware memory corrupts.
> > 
> > Unpoisoning a hardware corrupted page puts page back buddy only,
> > the kernel has a chance to access the page with *NOT PRESENT* KPTE.
> > This leads BUG during accessing on the corrupted KPTE.
> > 
> > Suggested by David&Naoya, disable unpoison mechanism when a real HW error
> > happens to avoid BUG like this:
> > 
>
> ...
>
> > 
> > Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support")
> > Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned")
> > Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
> > Cc: David Hildenbrand <david@redhat.com>
> > Cc: Oscar Salvador <osalvador@suse.de>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Acked-by: David Hildenbrand <david@redhat.com>
> > Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> 
> Thank you very much.
> 
> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>

I added cc:stable to this.  But the dual Fixes: are going to confuse
people regarding which kernel versions need the fix.  Can we be more
specific?