On 19.09.23 22:51, Stefan Roesch wrote:
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 <shr@xxxxxxxxxxxx>
---
tools/testing/selftests/mm/Makefile | 2 +
.../selftests/mm/ksm_fork_exec_child.c | 9 ++++
.../selftests/mm/ksm_functional_tests.c | 50 ++++++++++++++++++-
3 files changed, 60 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/mm/ksm_fork_exec_child.c
diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile
index 6a9fc5693145..9ab6aa402544 100644
--- a/tools/testing/selftests/mm/Makefile
+++ b/tools/testing/selftests/mm/Makefile
@@ -73,6 +73,8 @@ ifneq ($(ARCH),arm64)
TEST_GEN_PROGS += soft-dirty
endif
+TEST_GEN_PROGS += ksm_fork_exec_child
It's not a test itself, so it shouldn't be run when running all tests.
See below.
+
ifeq ($(ARCH),x86_64)
CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_32bit_program.c -m32)
CAN_BUILD_X86_64 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_64bit_program.c)
diff --git a/tools/testing/selftests/mm/ksm_fork_exec_child.c b/tools/testing/selftests/mm/ksm_fork_exec_child.c
new file mode 100644
index 000000000000..298439f0d55f
--- /dev/null
+++ b/tools/testing/selftests/mm/ksm_fork_exec_child.c
@@ -0,0 +1,9 @@
+#include <sys/prctl.h>
+#include <stdlib.h>
+
+int main()
+{
+ /* Test if KSM is enabled for the process. */
+ int ksm = prctl(68, 0, 0, 0, 0);
Can we use the define from a header? (PR_SET_MEMORY_MERGE)
I was wondering if we could simply exec() ourself (same binary), but
pass a special cmdline argument. Then you don't have to build a separate
binary.
Just special-case in main() on that argument and perform this check.
+ exit(ksm == 1 ? 0 : 1);
+}
diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
index 901e950f9138..4dc0bb522c07 100644
--- a/tools/testing/selftests/mm/ksm_functional_tests.c
+++ b/tools/testing/selftests/mm/ksm_functional_tests.c
@@ -479,6 +479,53 @@ static void test_prctl_fork(void)
ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n");
}
+static void test_prctl_fork_exec(void)
+{
+ int ret, status;
+ pid_t child_pid;
+
+ ksft_print_msg("[RUN] %s\n", __func__);
+
+ ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0);
+ if (ret < 0 && errno == EINVAL) {
+ ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n");
+ return;
+ } else if (ret) {
+ ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 failed\n");
+ return;
+ }
+
+ child_pid = fork();
+ if (child_pid == -1) {
+ ksft_test_result_skip("fork() failed\n");
+ return;
+ } else if (child_pid == 0) {
+ char *filename = "./ksm_fork_exec_child";
+ char *argv_for_program[] = { filename, NULL };
+
+ execv(filename, argv_for_program);;
s/;;/;/
Add a return; so you can simplify the code below (no need for the "else")
+ } else {
+ if (waitpid(child_pid, &status, 0) > 0) {
+ if (WIFEXITED(status)) {
+ status = 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;
+ }
+ }
+
+ ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n");
It's probably the cleanest to disable PR_SET_MEMORY_MERGE again when
returning form this function, so the other tests have a clean slate.
--
Cheers,
David / dhildenb
