From nobody Thu Dec 18 13:54:35 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35173CE7A86 for ; Fri, 22 Sep 2023 21:12:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229897AbjIVVMS (ORCPT ); Fri, 22 Sep 2023 17:12:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229798AbjIVVMK (ORCPT ); Fri, 22 Sep 2023 17:12:10 -0400 Received: from 66-220-144-178.mail-mxout.facebook.com (66-220-144-178.mail-mxout.facebook.com [66.220.144.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEF8BE8 for ; Fri, 22 Sep 2023 14:12:03 -0700 (PDT) Received: by devbig1114.prn1.facebook.com (Postfix, from userid 425415) id 9BCBFC60DC4E; Fri, 22 Sep 2023 14:11:50 -0700 (PDT) From: Stefan Roesch To: kernel-team@fb.com Cc: shr@devkernel.io, akpm@linux-foundation.org, david@redhat.com, hannes@cmpxchg.org, riel@surriel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v4 2/2] mm/ksm: Test case for prctl fork/exec workflow Date: Fri, 22 Sep 2023 14:11:41 -0700 Message-Id: <20230922211141.320789-3-shr@devkernel.io> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230922211141.320789-1-shr@devkernel.io> References: <20230922211141.320789-1-shr@devkernel.io> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This adds a new test case to the ksm functional tests to make sure that the KSM setting is inherited by the child process when doing a fork/exec. Signed-off-by: Stefan Roesch Reviewed-by: David Hildenbrand --- .../selftests/mm/ksm_functional_tests.c | 66 ++++++++++++++++++- 1 file changed, 65 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/test= ing/selftests/mm/ksm_functional_tests.c index 901e950f9138..fbff0dd09191 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/ksm_functional_tests.c @@ -26,6 +26,7 @@ =20 #define KiB 1024u #define MiB (1024 * KiB) +#define FORK_EXEC_CHILD_PRG_NAME "ksm_fork_exec_child" =20 static int mem_fd; static int ksm_fd; @@ -479,6 +480,64 @@ static void test_prctl_fork(void) ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n"); } =20 +static int ksm_fork_exec_child(void) +{ + /* Test if KSM is enabled for the process. */ + return prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0) =3D=3D 1; +} + +static void test_prctl_fork_exec(void) +{ + int ret, status; + pid_t child_pid; + + ksft_print_msg("[RUN] %s\n", __func__); + + ret =3D prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); + if (ret < 0 && errno =3D=3D EINVAL) { + ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); + return; + } else if (ret) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=3D1 failed\n"); + return; + } + + child_pid =3D fork(); + if (child_pid =3D=3D -1) { + ksft_test_result_skip("fork() failed\n"); + return; + } else if (child_pid =3D=3D 0) { + char *prg_name =3D "./ksm_functional_tests"; + char *argv_for_program[] =3D { prg_name, FORK_EXEC_CHILD_PRG_NAME }; + + execv(prg_name, argv_for_program); + return; + } + + if (waitpid(child_pid, &status, 0) > 0) { + if (WIFEXITED(status)) { + status =3D WEXITSTATUS(status); + if (status) { + ksft_test_result_fail("KSM not enabled\n"); + return; + } + } else { + ksft_test_result_fail("program didn't terminate normally\n"); + return; + } + } else { + ksft_test_result_fail("waitpid() failed\n"); + return; + } + + if (prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0)) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=3D0 failed\n"); + return; + } + + ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n"); +} + static void test_prctl_unmerge(void) { const unsigned int size =3D 2 * MiB; @@ -536,9 +595,13 @@ static void test_prot_none(void) =20 int main(int argc, char **argv) { - unsigned int tests =3D 7; + unsigned int tests =3D 8; int err; =20 + if (argc > 1 && !strcmp(argv[1], FORK_EXEC_CHILD_PRG_NAME)) { + exit(ksm_fork_exec_child() =3D=3D 1 ? 0 : 1); + } + #ifdef __NR_userfaultfd tests++; #endif @@ -576,6 +639,7 @@ int main(int argc, char **argv) =20 test_prctl(); test_prctl_fork(); + test_prctl_fork_exec(); test_prctl_unmerge(); =20 err =3D ksft_get_fail_cnt(); --=20 2.39.3