From 0c9d4199a72e880ccc058fed948a2fbe297c97e9 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Wed, 8 Apr 2015 09:44:33 +1000 Subject: [PATCH] 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: David Rientjes Cc: Jonathan Corbet Cc: Davide Libenzi Cc: Luiz Capitulino Cc: Shuah Khan Cc: Hugh Dickins Cc: Andrea Arcangeli Cc: Joern Engel Cc: Jianguo Wu Cc: Eric B Munson Acked-by: Michael Ellerman Signed-off-by: Andrew Morton --- tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c | 8 ++++++-- tools/testing/selftests/vm/hugetlbfstest.c | 4 +++- tools/testing/selftests/vm/map_hugetlb.c | 6 +++++- 3 files changed, 14 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c b/tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c index 3d8e5b033e1d..49003674de4f 100644 --- a/tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c +++ b/tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c @@ -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, diff --git a/tools/testing/selftests/vm/hugetlbfstest.c b/tools/testing/selftests/vm/hugetlbfstest.c index ea40ff8c2391..02e1072ec187 100644 --- a/tools/testing/selftests/vm/hugetlbfstest.c +++ b/tools/testing/selftests/vm/hugetlbfstest.c @@ -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"); diff --git a/tools/testing/selftests/vm/map_hugetlb.c b/tools/testing/selftests/vm/map_hugetlb.c index ac56639dd4a9..addcd6fc1ecc 100644 --- a/tools/testing/selftests/vm/map_hugetlb.c +++ b/tools/testing/selftests/vm/map_hugetlb.c @@ -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; } -- 2.39.5