selftests: mm: fix map_hugetlb failure on 64K page size systems

On systems with 64k page size and 512M huge page sizes, the allocation and
test succeeds but errors out at the munmap.  As the comment states, munmap
will failure if its not HUGEPAGE aligned.  This is due to the length of
the mapping being 1/2 the size of the hugepage causing the munmap to not
be hugepage aligned.  Fix this by making the mapping length the full
hugepage if the hugepage is larger than the length of the mapping.

Link: https://lkml.kernel.org/r/20240119131429.172448-1-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Cc: Donet Tom <donettom@linux.vnet.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/selftests/mm/map_hugetlb.c b/tools/testing/selftests/mm/map_hugetlb.c
index 193281560b61be23d3b55857030ea07b4ad3f95d..86e8f2048a409028b28ece3f755d06f535726c47 100644 (file)
--- a/tools/testing/selftests/mm/map_hugetlb.c
+++ b/tools/testing/selftests/mm/map_hugetlb.c
@@ -15,6 +15,7 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <fcntl.h>
+#include "vm_util.h"
 
 #define LENGTH (256UL*1024*1024)
 #define PROTECTION (PROT_READ | PROT_WRITE)
@@ -58,10 +59,16 @@ int main(int argc, char **argv)
 {
        void *addr;
        int ret;
+       size_t hugepage_size;
        size_t length = LENGTH;
        int flags = FLAGS;
        int shift = 0;
 
+       hugepage_size = default_huge_page_size();
+       /* munmap with fail if the length is not page aligned */
+       if (hugepage_size > length)
+               length = hugepage_size;
+
        if (argc > 1)
                length = atol(argv[1]) << 20;
        if (argc > 2) {