+ selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size.patch added to mm-nonmm-unstable branch

+ selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: selftests: secretmem: floor the memory size to the multiple of page_size
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Muhammad Usama Anjum <usama.anjum@collabora.com>
Subject: selftests: secretmem: floor the memory size to the multiple of page_size
Date: Thu, 14 Dec 2023 15:19:30 +0500

The "locked-in-memory size" limit per process can be non-multiple of
page_size.  The mmap() fails if we try to allocate locked-in-memory with
same size as the allowed limit if it isn't multiple of the page_size
because mmap() rounds off the memory size to be allocated to next multiple
of page_size.

Fix this by flooring the length to be allocated with mmap() to the
previous multiple of the page_size.

Link: https://lkml.kernel.org/r/20231214101931.1155586-1-usama.anjum@collabora.com
Fixes: 76fe17ef588a ("secretmem: test: add basic selftest for memfd_secret(2)")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/mm/memfd_secret.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/tools/testing/selftests/mm/memfd_secret.c~selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size
+++ a/tools/testing/selftests/mm/memfd_secret.c
@@ -62,6 +62,9 @@ static void test_mlock_limit(int fd)
 	char *mem;
 
 	len = mlock_limit_cur;
+	if (len % page_size != 0)
+		len = (len/page_size) * page_size;
+
 	mem = mmap(NULL, len, prot, mode, fd, 0);
 	if (mem == MAP_FAILED) {
 		fail("unable to mmap secret memory\n");
_

Patches currently in -mm which might be from usama.anjum@collabora.com are

selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size.patch