Re: [PATCH v2 00/13] selftests/mm: fix failures and robustness improvements

Andrew Morton
2026-03-12T22:05:31Z

On Thu, 12 Mar 2026 17:55:27 +0530 Sayali Patil <sayalip@linux.ibm.com> wrote:

> Hi all,
>
> Powerpc systems with a 64K base page size exposed several issues while
> running mm selftests. Some tests assume specific hugetlb configurations,
> use incorrect interfaces, or fail instead of skipping when the required
> kernel features are not available.
>
> This series fixes these issues and improves test robustness.

Thanks, I updated mm.git's mm-new branch to this version.

> ---
> v1->v2
> - For "selftests/mm: ensure destination is hugetlb-backed in hugepage-mremap":
> update FLAGS definition to MAP_HUGETLB | MAP_SHARED | MAP_POPULATE and
> used it for mmap() calls as suggested during review.

That was a really small change (below). It's better to wait a while
(half to one week) before resending an entire series. So as to
hopefully accumulate more changes.

--- a/tools/testing/selftests/mm/hugepage-mremap.c~b
+++ a/tools/testing/selftests/mm/hugepage-mremap.c
@@ -31,7 +31,7 @@
#define MB_TO_BYTES(x) (x * 1024 * 1024)

#define PROTECTION (PROT_READ | PROT_WRITE | PROT_EXEC)
-#define FLAGS (MAP_SHARED | MAP_ANONYMOUS)
+#define FLAGS (MAP_HUGETLB | MAP_SHARED | MAP_POPULATE)

static void check_bytes(char *addr)
{
@@ -121,23 +121,20 @@ int main(int argc, char *argv[])

/* mmap to a PUD aligned address to hopefully trigger pmd sharing. */
unsigned long suggested_addr = 0x7eaa40000000;
- void *haddr = mmap((void *)suggested_addr, length, PROTECTION,
- MAP_HUGETLB | MAP_SHARED | MAP_POPULATE, fd, 0);
+ void *haddr = mmap((void *)suggested_addr, length, PROTECTION, FLAGS, fd, 0);
ksft_print_msg("Map haddr: Returned address is %p\n", haddr);
if (haddr == MAP_FAILED)
ksft_exit_fail_msg("mmap1: %s\n", strerror(errno));

/* mmap again to a dummy address to hopefully trigger pmd sharing. */
suggested_addr = 0x7daa40000000;
- void *daddr = mmap((void *)suggested_addr, length, PROTECTION,
- MAP_HUGETLB | MAP_SHARED | MAP_POPULATE, fd, 0);
+ void *daddr = mmap((void *)suggested_addr, length, PROTECTION, FLAGS, fd, 0);
ksft_print_msg("Map daddr: Returned address is %p\n", daddr);
if (daddr == MAP_FAILED)
ksft_exit_fail_msg("mmap3: %s\n", strerror(errno));

suggested_addr = 0x7faa40000000;
- void *vaddr = mmap((void *)suggested_addr, length, PROTECTION,
- MAP_HUGETLB | MAP_SHARED | MAP_POPULATE, fd, 0);
+ void *vaddr = mmap((void *)suggested_addr, length, PROTECTION, FLAGS, fd, 0);
ksft_print_msg("Map vaddr: Returned address is %p\n", vaddr);
if (vaddr == MAP_FAILED)
ksft_exit_fail_msg("mmap2: %s\n", strerror(errno));
_