This is a note to let you know that I've just added the patch titled
selftests: secretmem: floor the memory size to the multiple of page_size
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0aac13add26d546ac74c89d2883b3a5f0fbea039 Mon Sep 17 00:00:00 2001
From: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Date: Thu, 14 Dec 2023 15:19:30 +0500
Subject: selftests: secretmem: floor the memory size to the multiple of page_size
From: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
commit 0aac13add26d546ac74c89d2883b3a5f0fbea039 upstream.
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.
This was getting triggered on KernelCI regularly because of different
ulimit settings which wasn't multiple of the page_size. Find logs
here: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/
The bug in was present from the time test was first added.
Link: https://lkml.kernel.org/r/20231214101931.1155586-1-usama.anjum@xxxxxxxxxxxxx
Fixes: 76fe17ef588a ("secretmem: test: add basic selftest for memfd_secret(2)")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Reported-by: "kernelci.org bot" <bot@xxxxxxxxxxxx>
Closes: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/
Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/mm/memfd_secret.c | 3 +++
1 file changed, 3 insertions(+)
--- a/tools/testing/selftests/mm/memfd_secret.c
+++ b/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 stable-queue which might be from usama.anjum@xxxxxxxxxxxxx are
queue-6.6/selftests-secretmem-floor-the-memory-size-to-the-multiple-of-page_size.patch
