lkml.org 
[lkml]   [2021]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm: Fix potential pte_unmap_unlock pte error
On Fri, 22 Jan 2021 16:27:23 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:

> Hi Andrew:
> On 2021/1/14 10:51, Miaohe Lin wrote:
> > Hi:
> > On 2021/1/11 1:14, Andi Kleen wrote:
> >> On Sat, Jan 09, 2021 at 03:01:18AM -0500, Miaohe Lin wrote:
> >>> Since commit 42e4089c7890 ("x86/speculation/l1tf: Disallow non privileged
> >>> high MMIO PROT_NONE mappings"), when the first pfn modify is not allowed,
> >>> we would break the loop with pte unchanged. Then the wrong pte - 1 would
> >>> be passed to pte_unmap_unlock.
> >>
> >> Thanks.
> >>
> >> While the fix is correct, I'm not sure if it actually is a real bug. Is there
> >> any architecture that would do something else than unlocking the underlying
> >> page? If it's just the underlying page then it should be always the same
> >> page, so no bug.
> >>
> >
> > It's just a theoretical issue via code inspection.
>
> Should I send a new one without Cc statle or just drop this patch? Thanks.

Your patch makes the code much less scary looking. I added Andi's
observation to the changelog, removed the cc:stable and queued it up,
thanks.

\
 
 \ /
  Last update: 2021-01-24 03:03    [W:0.090 / U:4.816 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site