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

[David Hildenbrand (Arm)]

On 10/2/26 19:56, Ameer Hamza wrote:
> Hi,
> 

Hi!

> 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
> with EFAULT. This happens for root as well as for an unprivileged
> user running its own perf record. It reproduces on v7.3-rc4 and
> 6.18.52, and the same test passes without the recording or with the
> commit reverted.

Thanks for the report!

May I know whether this problem was found by

(a) A real workload

(b) A test case

(c) Complains by some tooling

I am asking, because so far I was under the assumption that secretmem isn't
heavily used in the wild.

-- 
Cheers,

David