On Mon, 13 Feb 2023, Shaopeng Tan wrote:
> After creating a child process with fork() in CAT test, if a signal such
> as SIGINT is received, the parent process will be terminated immediately,
> and therefor the child process will not be killed and also resctrlfs is
therefore
> not unmounted.
>
> There is a signal handler registered in CMT/MBM/MBA tests, which kills
> child process, unmount resctrlfs, cleanups result files, etc., if a
> signal such as SIGINT is received.
>
> Commonize the signal handler registered for CMT/MBM/MBA tests and
> reuse it in CAT.
>
> To reuse the signal handler to kill child process use global bm_pid
> instead of local bm_pid.
>
> Also, since the MBA/MBA/CMT/CAT are run in order, unregister the signal
> handler at the end of each test so that the signal handler cannot be
> inherited by other tests.
>
> Signed-off-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
This looks okay.
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
As a general comment, it would be probably nicer structure to put all
IPC related code into ipc.c rather than have it in the test related files
(mainly signal handling, pipe write/wait).
> ---
> tools/testing/selftests/resctrl/cat_test.c | 9 ++-
> tools/testing/selftests/resctrl/fill_buf.c | 14 ----
> tools/testing/selftests/resctrl/resctrl.h | 2 +
> tools/testing/selftests/resctrl/resctrl_val.c | 66 ++++++++++++++-----
> 4 files changed, 58 insertions(+), 33 deletions(-)
>
> diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
> index 477b62dac546..0bdf0305a506 100644
> --- a/tools/testing/selftests/resctrl/cat_test.c
> +++ b/tools/testing/selftests/resctrl/cat_test.c
> @@ -103,7 +103,6 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
> unsigned long l_mask, l_mask_1;
> int ret, pipefd[2], sibling_cpu_no;
> char pipe_message;
> - pid_t bm_pid;
>
> cache_size = 0;
>
> @@ -181,6 +180,12 @@ 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 {
> + ret = signal_handler_register();
> + if (ret) {
> + kill(bm_pid, SIGKILL);
> + goto out;
> + }
> }
>
> remove(param.filename);
> @@ -217,8 +222,10 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
> }
> close(pipefd[0]);
> kill(bm_pid, SIGKILL);
> + signal_handler_unregister();
> }
>
> +out:
> cat_test_cleanup();
> if (bm_pid)
> umount_resctrlfs();
> diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
> index 56ccbeae0638..322c6812e15c 100644
> --- a/tools/testing/selftests/resctrl/fill_buf.c
> +++ b/tools/testing/selftests/resctrl/fill_buf.c
> @@ -33,14 +33,6 @@ static void sb(void)
> #endif
> }
>
> -static void ctrl_handler(int signo)
> -{
> - free(startptr);
> - printf("\nEnding\n");
> - sb();
> - exit(EXIT_SUCCESS);
> -}
> -
> static void cl_flush(void *p)
> {
> #if defined(__i386) || defined(__x86_64)
> @@ -198,12 +190,6 @@ int run_fill_buf(unsigned long span, int malloc_and_init_memory,
> unsigned long long cache_size = span;
> int ret;
>
> - /* set up ctrl-c handler */
> - if (signal(SIGINT, ctrl_handler) == SIG_ERR)
> - printf("Failed to catch SIGINT!\n");
> - if (signal(SIGHUP, ctrl_handler) == SIG_ERR)
> - printf("Failed to catch SIGHUP!\n");
> -
> ret = fill_cache(cache_size, malloc_and_init_memory, memflush, op,
> resctrl_val);
> if (ret) {
> diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
> index f0ded31fb3c7..92b59d2f603d 100644
> --- a/tools/testing/selftests/resctrl/resctrl.h
> +++ b/tools/testing/selftests/resctrl/resctrl.h
> @@ -107,6 +107,8 @@ void mba_test_cleanup(void);
> int get_cbm_mask(char *cache_type, char *cbm_mask);
> int get_cache_size(int cpu_no, char *cache_type, unsigned long *cache_size);
> void ctrlc_handler(int signum, siginfo_t *info, void *ptr);
> +int signal_handler_register(void);
> +void signal_handler_unregister(void);
> int cat_val(struct resctrl_val_param *param);
> void cat_test_cleanup(void);
> int cat_perf_miss_val(int cpu_no, int no_of_bits, char *cache_type);
> diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c
> index 6948843bf995..7c8d5c25e6da 100644
> --- a/tools/testing/selftests/resctrl/resctrl_val.c
> +++ b/tools/testing/selftests/resctrl/resctrl_val.c
> @@ -476,6 +476,45 @@ void ctrlc_handler(int signum, siginfo_t *info, void *ptr)
> exit(EXIT_SUCCESS);
> }
>
> +/*
> + * Register CTRL-C handler for parent, as it has to kill
> + * child process before exiting.
> + */
> +int signal_handler_register(void)
> +{
> + struct sigaction sigact;
> + int ret = 0;
> +
> + 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");
> + ret = -1;
> + }
> + return ret;
> +}
> +
> +/*
> + * Reset signal handler to SIG_DFL.
> + * Non-Value return because the caller should keep
> + * the error code of other path even if sigaction fails.
> + */
> +void signal_handler_unregister(void)
> +{
> + struct sigaction sigact;
> +
> + sigact.sa_handler = SIG_DFL;
> + sigemptyset(&sigact.sa_mask);
> + if (sigaction(SIGINT, &sigact, NULL) ||
> + sigaction(SIGTERM, &sigact, NULL) ||
> + sigaction(SIGHUP, &sigact, NULL)) {
> + perror("# sigaction");
> + }
> +}
> +
> /*
> * print_results_bw: the memory bandwidth results are stored in a file
> * @filename: file that stores the results
> @@ -671,39 +710,28 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
>
> ksft_print_msg("Benchmark PID: %d\n", bm_pid);
>
> - /*
> - * Register CTRL-C handler for parent, as it has to kill benchmark
> - * 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");
> - ret = errno;
> + ret = signal_handler_register();
> + if (ret)
> goto out;
> - }
>
> value.sival_ptr = benchmark_cmd;
>
> /* Taskset benchmark to specified cpu */
> ret = taskset_benchmark(bm_pid, param->cpu_no);
> if (ret)
> - goto out;
> + goto unregister;
>
> /* Write benchmark to specified control&monitoring grp in resctrl FS */
> ret = write_bm_pid_to_resctrl(bm_pid, param->ctrlgrp, param->mongrp,
> resctrl_val);
> if (ret)
> - goto out;
> + goto unregister;
>
> if (!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) ||
> !strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR))) {
> ret = initialize_mem_bw_imc();
> if (ret)
> - goto out;
> + goto unregister;
>
> initialize_mem_bw_resctrl(param->ctrlgrp, param->mongrp,
> param->cpu_no, resctrl_val);
> @@ -718,7 +746,7 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
> sizeof(pipe_message)) {
> perror("# failed reading message from child process");
> close(pipefd[0]);
> - goto out;
> + goto unregister;
> }
> }
> close(pipefd[0]);
> @@ -727,7 +755,7 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
> if (sigqueue(bm_pid, SIGUSR1, value) == -1) {
> perror("# sigqueue SIGUSR1 to child");
> ret = errno;
> - goto out;
> + goto unregister;
> }
>
> /* Give benchmark enough time to fully run */
> @@ -761,6 +789,8 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
> }
> }
>
> +unregister:
> + signal_handler_unregister();
> out:
> kill(bm_pid, SIGKILL);
> umount_resctrlfs();
>
