[PATCH v4 4/5] selftests/resctrl: Cleanup properly when an error occurs in CAT test

From: Shaopeng Tan
Date: Wed Nov 16 2022 - 20:11:57 EST


After creating a child process with fork() in CAT test, if there is
an error occurs or such as a SIGINT signal is received, the parent
process will be terminated immediately, but the child process will not
be killed and also umount_resctrlfs() will not be called.

Add a signal handler like other tests to kill child process, umount
resctrlfs, cleanup result files, etc. if an error occurs in parent
process. To use ctrlc_handler() of other tests to kill child
process(bm_pid), using global bm_pid instead of local bm_pid.

Wait for child process to be killed if an error occurs in child process.

Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
---
tools/testing/selftests/resctrl/cat_test.c | 30 ++++++++++++++--------
1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index 6a8306b0a109..1f8f5cf94e95 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -100,10 +100,10 @@ void cat_test_cleanup(void)

int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
{
+ struct sigaction sigact;
unsigned long l_mask, l_mask_1;
int ret, pipefd[2], sibling_cpu_no;
char pipe_message;
- pid_t bm_pid;

cache_size = 0;

@@ -181,17 +181,25 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
strcpy(param.filename, RESULT_FILE_NAME1);
param.num_of_runs = 0;
param.cpu_no = sibling_cpu_no;
+ } else {
+ /*
+ * Register CTRL-C handler for parent, as it has to kill
+ * child process before exiting
+ */
+ sigact.sa_sigaction = ctrlc_handler;
+ sigemptyset(&sigact.sa_mask);
+ sigact.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGINT, &sigact, NULL) ||
+ sigaction(SIGTERM, &sigact, NULL) ||
+ sigaction(SIGHUP, &sigact, NULL))
+ perror("# sigaction");
}

remove(param.filename);

ret = cat_val(&param);
- if (ret)
- return ret;
-
- ret = check_results(&param);
- if (ret)
- return ret;
+ if (ret == 0)
+ ret = check_results(&param);

if (bm_pid == 0) {
/* Tell parent that child is ready */
@@ -199,9 +207,11 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
pipe_message = 1;
if (write(pipefd[1], &pipe_message, sizeof(pipe_message)) <
sizeof(pipe_message)) {
- close(pipefd[1]);
+ /*
+ * Just print the error message.
+ * Let while(1) run and wait for itself to be killed.
+ */
perror("# failed signaling parent process");
- return errno;
}

close(pipefd[1]);
@@ -226,5 +236,5 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
if (bm_pid)
umount_resctrlfs();

- return 0;
+ return ret;
}
--
2.27.0