Re: [REGRESSION] secretmem: SIGBUS on memfd_secret() pages while perf record runs

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Fri, Oct 02, 2026 at 09:30:23PM -0400, Sasha Levin wrote:
> > Since commit 97d34aa65c29 ("mm/secretmem: properly account locked
> > pages"), in v7.3-rc2 and the 6.18.52 and 7.2.5 backports, touching a
> > memfd_secret() page for the first time fails with SIGBUS while the
> > same user is running perf record, and read() into such a page fails
>
> Thanks for the report. I've dropped 97d34aa65c29 from the 6.12 queue,
> and also removed the copies that were staged for 6.6 and 6.1.
>
> 7.2.y and 6.18.y already shipped it, so those need an upstream fix,
> which stable will pick up once it lands.

Sasha,

Could we perhaps take a breath and pause?

This patch fixes a really quite serious vulnerability that allows an
unprivileged process to allocate arbitrary, unreclaimable (i.e. OOMK cannot
save you) memory.

Allow me to assess the validity of this report _before_ dropping things
from queues perhaps? :)

It was sent late on Friday in a week that I was ill and it's Saturday
pre-LPC, so that's hardly a timeframe that I could reasonably have replied.

Thanks!

--
Cheers, Lorenzo