In ksm_functional_tests, test_child_ksm() returned negative values to indicate errors. However, when passed to exit(), these were interpreted as large unsigned values (e.g, -2 became 254), leading to incorrect handling in the parent process. As a result, some tests appeared to be skipped or silently failed. This patch changes test_child_ksm() to return positive error codes (1, 2, 3) and updates test_child_ksm_err() to interpret them correctly. Additionally, test_prctl_fork_exec() now uses exit(4) after a failed execv() to clearly signal exec failures. This ensures the parent accurately detects and reports child process failures. -------------- Before patch: -------------- - [RUN] test_unmerge ok 1 Pages were unmerged ... - [RUN] test_prctl_fork - No pages got merged - [RUN] test_prctl_fork_exec ok 7 PR_SET_MEMORY_MERGE value is inherited ... Bail out! 1 out of 8 tests failed - Planned tests != run tests (9 != 8) - Totals: pass:7 fail:1 xfail:0 xpass:0 skip:0 error:0 -------------- After patch: -------------- - [RUN] test_unmerge ok 1 Pages were unmerged ... - [RUN] test_prctl_fork - No pages got merged not ok 7 Merge in child failed - [RUN] test_prctl_fork_exec ok 8 PR_SET_MEMORY_MERGE value is inherited ... Bail out! 2 out of 9 tests failed - Totals: pass:7 fail:2 xfail:0 xpass:0 skip:0 error:0 Fixes: 6c47de3be3a0 ("selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec") Co-developed-by: Donet Tom Signed-off-by: Donet Tom Acked-by: David Hildenbrand Signed-off-by: Aboorva Devarajan --- .../testing/selftests/mm/ksm_functional_tests.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c index 996dc6645570..534aa405cac7 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/ksm_functional_tests.c @@ -512,14 +512,14 @@ static int test_child_ksm(void) /* Test if KSM is enabled for the process. */ if (prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0) != 1) - return -1; + return 1; /* Test if merge could really happen. */ map = __mmap_and_merge_range(0xcf, size, PROT_READ | PROT_WRITE, KSM_MERGE_NONE); if (map == MAP_MERGE_FAIL) - return -2; + return 2; else if (map == MAP_MERGE_SKIP) - return -3; + return 3; ksm_unmerge(); munmap(map, size); @@ -528,12 +528,14 @@ static int test_child_ksm(void) static void test_child_ksm_err(int status) { - if (status == -1) + if (status == 1) ksft_test_result_fail("unexpected PR_GET_MEMORY_MERGE result in child\n"); - else if (status == -2) + else if (status == 2) ksft_test_result_fail("Merge in child failed\n"); - else if (status == -3) + else if (status == 3) ksft_test_result_skip("Merge in child skipped\n"); + else if (status == 4) + ksft_test_result_fail("Binary not found\n"); } /* Verify that prctl ksm flag is inherited. */ @@ -606,7 +608,7 @@ static void test_prctl_fork_exec(void) char *argv_for_program[] = { prg_name, FORK_EXEC_CHILD_PRG_NAME, NULL }; execv(prg_name, argv_for_program); - return; + exit(4); } if (waitpid(child_pid, &status, 0) > 0) { -- 2.47.1