Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 215ba781 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, selftests: test return value of munmap for MAP_HUGETLB memory 



When MAP_HUGETLB memory is unmapped, the length must be hugepage aligned,
otherwise it fails with -EINVAL.

All tests currently behave correctly, but it's better to explcitly test
the return value for completeness and document the requirement, especially
if users copy map_hugetlb.c as a sample implementation.

Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Eric B Munson <emunson@akamai.com>
Acked-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 80d6b94b

tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c

+6 −2
Original line number Diff line number Diff line
@@ -21,9 +21,13 @@ static int test_body(void) 
		 * Typically the mmap will fail because no huge pages are

		 * allocated on the system. But if there are huge pages

		 * allocated the mmap will succeed. That's fine too, we just

		 * munmap here before continuing.

		 * munmap here before continuing.  munmap() length of

		 * MAP_HUGETLB memory must be hugepage aligned.

		 */

		munmap(addr, SIZE);

		if (munmap(addr, SIZE)) {

			perror("munmap");

			return 1;

		}

	}



	p = mmap(addr, SIZE, PROT_READ | PROT_WRITE,

tools/testing/selftests/vm/hugetlbfstest.c

+3 −1
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ static void do_mmap(int fd, int extra_flags, int unmap) 
	int *p;

	int flags = MAP_PRIVATE | MAP_POPULATE | extra_flags;

	u64 before, after;

	int ret;



	before = read_rss();

	p = mmap(NULL, length, PROT_READ | PROT_WRITE, flags, fd, 0);
@@ -44,7 +45,8 @@ static void do_mmap(int fd, int extra_flags, int unmap) 
			!"rss didn't grow as expected");

	if (!unmap)

		return;

	munmap(p, length);

	ret = munmap(p, length);

	assert(!ret || !"munmap returned an unexpected error");

	after = read_rss();

	assert(llabs(after - before) < 0x40000 ||

			!"rss didn't shrink as expected");

tools/testing/selftests/vm/map_hugetlb.c

+5 −1
Original line number Diff line number Diff line
@@ -73,7 +73,11 @@ int main(void) 
	write_bytes(addr);

	ret = read_bytes(addr);



	munmap(addr, LENGTH);

	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */

	if (munmap(addr, LENGTH)) {

		perror("munmap");

		exit(1);

	}



	return ret;

}