[merged mm-stable] selftests-mm-reduce-uffd-unit-test-poison-test-to-minimum.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: selftests/mm: reduce uffd-unit-test poison test to minimum
has been removed from the -mm tree.  Its filename was
     selftests-mm-reduce-uffd-unit-test-poison-test-to-minimum.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
Subject: selftests/mm: reduce uffd-unit-test poison test to minimum
Date: Fri, 20 Jun 2025 11:00:58 -0400

The test will still generate quite some unwanted MCE error messages to
syslog.  There was old proposal ratelimiting the MCE messages from kernel,
but that has risk of hiding real useful information on production systems.

We can at least reduce the test to minimum to not over-pollute dmesg,
however trying to not lose its coverage too much.

[peterx@redhat.com: reduce uffd-unit-test poison test to minimum]
  Link: https://lkml.kernel.org/r/aF2RSsjuEOtzXcUa@x1.local
Link: https://lkml.kernel.org/r/20250620150058.1729489-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/uffd-unit-tests.c |   20 +++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

--- a/tools/testing/selftests/mm/uffd-unit-tests.c~selftests-mm-reduce-uffd-unit-test-poison-test-to-minimum
+++ a/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -1027,6 +1027,9 @@ static void uffd_poison_handle_fault(
 		do_uffdio_poison(uffd, offset);
 }
 
+/* Make sure to cover odd/even, and minimum duplications */
+#define  UFFD_POISON_TEST_NPAGES  4
+
 static void uffd_poison_test(uffd_test_args_t *targs)
 {
 	pthread_t uffd_mon;
@@ -1034,12 +1037,17 @@ static void uffd_poison_test(uffd_test_a
 	struct uffd_args args = { 0 };
 	struct sigaction act = { 0 };
 	unsigned long nr_sigbus = 0;
-	unsigned long nr;
+	unsigned long nr, poison_pages = UFFD_POISON_TEST_NPAGES;
+
+	if (nr_pages < poison_pages) {
+		uffd_test_skip("Too few pages for POISON test");
+		return;
+	}
 
 	fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK);
 
-	uffd_register_poison(uffd, area_dst, nr_pages * page_size);
-	memset(area_src, 0, nr_pages * page_size);
+	uffd_register_poison(uffd, area_dst, poison_pages * page_size);
+	memset(area_src, 0, poison_pages * page_size);
 
 	args.handle_fault = uffd_poison_handle_fault;
 	if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args))
@@ -1051,7 +1059,7 @@ static void uffd_poison_test(uffd_test_a
 	if (sigaction(SIGBUS, &act, 0))
 		err("sigaction");
 
-	for (nr = 0; nr < nr_pages; ++nr) {
+	for (nr = 0; nr < poison_pages; ++nr) {
 		unsigned long offset = nr * page_size;
 		const char *bytes = (const char *) area_dst + offset;
 		const char *i;
@@ -1078,9 +1086,9 @@ static void uffd_poison_test(uffd_test_a
 	if (pthread_join(uffd_mon, NULL))
 		err("pthread_join()");
 
-	if (nr_sigbus != nr_pages / 2)
+	if (nr_sigbus != poison_pages / 2)
 		err("expected to receive %lu SIGBUS, actually received %lu",
-		    nr_pages / 2, nr_sigbus);
+		    poison_pages / 2, nr_sigbus);
 
 	uffd_test_pass();
 }
_

Patches currently in -mm which might be from peterx@redhat.com are

mm-hugetlb-remove-prepare_hugepage_range.patch
mm-deduplicate-mm_get_unmapped_area.patch