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@linutronix.de
Acked-by: David Hildenbrand david@redhat.com