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

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
......@@ -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,
......
......@@ -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");
......
......@@ -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;
}
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment