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 <rientjes@xxxxxxxxxx>
---
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
--- 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
--- 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
--- 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;
}
--
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