On Thu, Nov 13, 2025 at 03:46:22AM +0000, Carlos Llamas wrote:
Commit 4dfd4bba8578 ("selftests/mm/uffd: refactor non-composite global vars into struct") moved some of the operations previously implemented in uffd_setup_environment() earlier in the main test loop.
The calculation of nr_pages, which involves a division by page_size, now occurs before checking that default_huge_page_size() returns a non-zero This leads to a division-by-zero error on systems with !CONFIG_HUGETLB.
Fix this by relocating the non-zero page_size check before the nr_pages calculation, as it was originally implemented.
Cc: stable@vger.kernel.org Fixes: 4dfd4bba8578 ("selftests/mm/uffd: refactor non-composite global vars into struct") Signed-off-by: Carlos Llamas cmllamas@google.com
Agree with what David and Lorenzo said about cc:stable.
Reviewed-by: Mike Rapoport (Microsoft) rppt@kernel.org
tools/testing/selftests/mm/uffd-unit-tests.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index 9e3be2ee7f1b..f917b4c4c943 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -1758,10 +1758,15 @@ int main(int argc, char *argv[]) uffd_test_ops = mem_type->mem_ops; uffd_test_case_ops = test->test_case_ops;
if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB))
if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB)) { gopts.page_size = default_huge_page_size();
else
if (gopts.page_size == 0) {uffd_test_skip("huge page size is 0, feature missing?");continue;}} else { gopts.page_size = psize();}/* Ensure we have at least 2 pages */ gopts.nr_pages = MAX(UFFD_TEST_MEM_SIZE, gopts.page_size * 2) @@ -1776,12 +1781,6 @@ int main(int argc, char *argv[]) continue; uffd_test_start("%s on %s", test->name, mem_type->name);
if ((mem_type->mem_flag == MEM_HUGETLB ||mem_type->mem_flag == MEM_HUGETLB_PRIVATE) &&(default_huge_page_size() == 0)) {uffd_test_skip("huge page size is 0, feature missing?");continue;} if (!uffd_feature_supported(test)) { uffd_test_skip("feature missing"); continue;-- 2.51.2.1041.gc1ab5b90ca-goog