On 12/15/23 3:59 PM, Mike Rapoport wrote:
On Thu, Dec 14, 2023 at 03:19:30PM +0500, Muhammad Usama Anjum wrote:
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.
Fixes: 76fe17ef588a ("secretmem: test: add basic selftest for memfd_secret(2)") Reported-by: "kernelci.org bot" bot@kernelci.org Signed-off-by: Muhammad Usama Anjum usama.anjum@collabora.com
tools/testing/selftests/mm/memfd_secret.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/testing/selftests/mm/memfd_secret.c b/tools/testing/selftests/mm/memfd_secret.c index 957b9e18c729..9b298f6a04b3 100644 --- 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;With mlock limit smaller than a page we get zero length here and mmap will fail with -EINVAL because of it.
This test has a initialization step in prepare() where it increases the limit to at least a page if it is less than a page. Hence we'll never get len = 0 here.
In this case I think we can just skip the first mmap and only check that mmaping more than mlock limit fails.
mem = mmap(NULL, len, prot, mode, fd, 0); if (mem == MAP_FAILED) { fail("unable to mmap secret memory\n"); -- 2.42.0