Re: [PATCH RFC v2 6/7] KVM: selftests: Add memory failure tests in guest_memfd_test

[Lisa Wang <wyihan@google.com>]

On Mon, Mar 30, 2026 at 03:20:15PM +0800, Miaohe Lin wrote:
> On 2026/3/20 7:30, Lisa Wang wrote:
> > After modifying truncate_error_folio(), we expect memory_failure() will
> > return 0 instead of MF_FAILED. Also, we want to make sure memory_failure()
> > signaling function is same.
> > 
> > Test that memory_failure() returns 0 for guest_memfd, where
> > .error_remove_folio() is handled by not actually truncating, and returning
> > MF_DELAYED.
> > 
> > In addition, test that SIGBUS signaling behavior is not changed before
> > and after this modification.
> > 
> > There are two kinds of guest memory failure injections - madvise or
> > debugfs. When memory failure is injected using madvise, the
> > MF_ACTION_REQUIRED flag is set, and the page is mapped and dirty, the
> > process should get a SIGBUS. When memory is failure is injected using
> > debugfs, the KILL_EARLY machine check memory corruption kill policy is
> > set, and the page is mapped and dirty, the process should get a SIGBUS.
> > 
> > Co-developed-by: Ackerley Tng <ackerleytng@google.com>
> > Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> > Signed-off-by: Lisa Wang <wyihan@google.com>
> 
> Should we add a testcase for hugetlbfs? It seems hugetlbfs_error_remove_folio() behaves same as shmem.

I agree that it would be more consistent to modify
hugetlbfs_error_remove_folio() to return MF_DELAYED and update
me_huge_page() to align with me_pagecache_clean().

However, I prefer to let this patch series focus on the
me_pagecache_clean() path (affecting shmem, guest_memfd and generic
pagecache), because the hugepage memory failure test is not working now
(hugetlb-read-hwpoison.c). Commit 66802526298e changed madvise()
behavior to always force-deliver a SIGBUS to the calling process if it
has the poisoned dirty page mapped. Aligning HugeTLB would require us to
fix this part together.

To keep this series focused, I would like to handle the HugeTLB
alignment in the follow-up series. Would you be okay with this approach?

> Thanks.
> .