The idea of adv_mmap tests is to map/unmap pages in arbitrary
order. It works fine as soon as the kernel allocates first 3 pages
for from a region with unallocated page after that. If it's not the
case, the last remapping of 4 pages with MAP_FIXED will remap the
page to bpf map which will break the code which worked with the data
located there before.
Change the test to map first the whole bpf map, 4 pages, and then
manipulate the mappings.
Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx>
---
tools/testing/selftests/bpf/prog_tests/mmap.c | 23 ++++++++++++-------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/mmap.c b/tools/testing/selftests/bpf/prog_tests/mmap.c
index 43d0b5578f46..5768af1e16a7 100644
--- a/tools/testing/selftests/bpf/prog_tests/mmap.c
+++ b/tools/testing/selftests/bpf/prog_tests/mmap.c
@@ -183,38 +183,45 @@ void test_mmap(void)
/* check some more advanced mmap() manipulations */
- /* map all but last page: pages 1-3 mapped */
- tmp1 = mmap(NULL, 3 * page_size, PROT_READ, MAP_SHARED,
+ /* map all 4 pages */
+ tmp1 = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED,
data_map_fd, 0);
if (CHECK(tmp1 == MAP_FAILED, "adv_mmap1", "errno %d\n", errno))
goto cleanup;
- /* unmap second page: pages 1, 3 mapped */
+ /* unmap second page: pages 1, 3, 4 mapped */
err = munmap(tmp1 + page_size, page_size);
if (CHECK(err, "adv_mmap2", "errno %d\n", errno)) {
munmap(tmp1, map_sz);
goto cleanup;
}
+ /* unmap forth page: pages 1, 3 mapped */
+ err = munmap(tmp1 + (3 * page_size), page_size);
+ if (CHECK(err, "adv_mmap3", "errno %d\n", errno)) {
+ munmap(tmp1, map_sz);
+ goto cleanup;
+ }
+
/* map page 2 back */
tmp2 = mmap(tmp1 + page_size, page_size, PROT_READ,
MAP_SHARED | MAP_FIXED, data_map_fd, 0);
- if (CHECK(tmp2 == MAP_FAILED, "adv_mmap3", "errno %d\n", errno)) {
+ if (CHECK(tmp2 == MAP_FAILED, "adv_mmap4", "errno %d\n", errno)) {
munmap(tmp1, page_size);
munmap(tmp1 + 2*page_size, page_size);
goto cleanup;
}
- CHECK(tmp1 + page_size != tmp2, "adv_mmap4",
+ CHECK(tmp1 + page_size != tmp2, "adv_mmap5",
"tmp1: %p, tmp2: %p\n", tmp1, tmp2);
/* re-map all 4 pages */
tmp2 = mmap(tmp1, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
data_map_fd, 0);
- if (CHECK(tmp2 == MAP_FAILED, "adv_mmap5", "errno %d\n", errno)) {
+ if (CHECK(tmp2 == MAP_FAILED, "adv_mmap6", "errno %d\n", errno)) {
munmap(tmp1, 3 * page_size); /* unmap page 1 */
goto cleanup;
}
- CHECK(tmp1 != tmp2, "adv_mmap6", "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
+ CHECK(tmp1 != tmp2, "adv_mmap7", "tmp1: %p, tmp2: %p\n", tmp1, tmp2);
map_data = tmp2;
CHECK_FAIL(bss_data->in_val != 321);
@@ -231,7 +238,7 @@ void test_mmap(void)
/* map all 4 pages, but with pg_off=1 page, should fail */
tmp1 = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED | MAP_FIXED,
data_map_fd, page_size /* initial page shift */);
- if (CHECK(tmp1 != MAP_FAILED, "adv_mmap7", "unexpected success")) {
+ if (CHECK(tmp1 != MAP_FAILED, "adv_mmap8", "unexpected success")) {
munmap(tmp1, 4 * page_size);
goto cleanup;
}
--
2.26.2
