On 11.03.25 11:38, Cyan Yang wrote:
On Tue, Mar 11, 2025 at 10:19:32AM +0100, David Hildenbrand wrote:
On 11.03.25 03:37, Cyan Yang wrote:
There are two error handlings did not check the correct return value.
This patch will fix them.

Fixes: f4b5fd6946e244cdedc3bbb9a1f24c8133b2077a ("selftests/vm: anon_cow: THP 
tests")
Signed-off-by: Cyan Yang <[email protected]>
---
   tools/testing/selftests/mm/cow.c | 4 ++--
   1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
index 9446673645eb..16fcadc090a4 100644
--- a/tools/testing/selftests/mm/cow.c
+++ b/tools/testing/selftests/mm/cow.c
@@ -876,13 +876,13 @@ static void do_run_with_thp(test_fn fn, enum thp_run 
thp_run, size_t thpsize)
                mremap_size = thpsize / 2;
                mremap_mem = mmap(NULL, mremap_size, PROT_NONE,
                                  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-               if (mem == MAP_FAILED) {
+               if (mremap_mem == MAP_FAILED) {
                        ksft_test_result_fail("mmap() failed\n");
                        goto munmap;
                }

Yes, that check is wrong.

                tmp = mremap(mem + mremap_size, mremap_size, mremap_size,
                             MREMAP_MAYMOVE | MREMAP_FIXED, mremap_mem);
-               if (tmp != mremap_mem) {
+               if (tmp == MAP_FAILED) {
                        ksft_test_result_fail("mremap() failed\n");
                        goto munmap;
                }

As Dev says, this one is just fine. Leave it as it is.


Thank you for the review.

I agree with you and Dev this is just fine. The reason I prefer to modify it is
- usually caller checks the return value directly and "tmp == mremap_mem"
should be determined by "mremap".

If you still prefer to leave it as it is, I will send out the v2 to remove it.

Yes, leave it as is. This does not belong in this fix for a real error checking problem. Thanks!

--
Cheers,

David / dhildenb


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