Re: [PATCH v3 2/4] selftests/mm: virtual_address_range: Unmap chunks after validation

[David Hildenbrand]

On 13.01.25 14:15, Thomas Weißschuh wrote:
> For each accessed chunk a PTE is created.
> More than 1GiB of PTEs is used in this way.
> Remove each PTE after validating a chunk to reduce peak memory usage.
>
> It is important to only unmap memory that previously mmap()ed,
> as unmapping other mappings like the stack, heap or executable mappings
> will crash the process.
> The mappings read from /proc/self/maps and the return values from mmap()
> don't allow a simple correlation due to merging and no guaranteed order.
> To correlate the pointers and mappings use prctl(PR_SET_VMA_ANON_NAME).
> While it introduces a test dependency, other alternatives would
> introduce runtime or development overhead.
>
> Fixes: 010409649885 ("selftests/mm: confirm VA exhaustion without reliance on correctness of mmap()")
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
> ---

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

--
Cheers,

David / dhildenb