Some benchmarks don't have either "consumer" or "producer" sides. For example, trig-tp and other BPF triggering benchmarks don't have consumers, as they only do "producing" by calling into syscall or predefined uproes. As such it's valid for some benchmarks to have zero consumers or producers. So allows to specify `-c0` explicitly. This triggers another problem. If benchmark doesn't support either consumer or producer side, consumer_thread/producer_thread callback will be NULL, but benchmark runner will attempt to use those NULL callback to create threads anyways. So instead of crashing with SIGSEGV in case of misconfigured benchmark, detect the condition and report error. Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> --- tools/testing/selftests/bpf/bench.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/bench.c b/tools/testing/selftests/bpf/bench.c index 73ce11b0547d..1724d50ba942 100644 --- a/tools/testing/selftests/bpf/bench.c +++ b/tools/testing/selftests/bpf/bench.c @@ -323,14 +323,14 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state) break; case 'p': env.producer_cnt = strtol(arg, NULL, 10); - if (env.producer_cnt <= 0) { + if (env.producer_cnt < 0) { fprintf(stderr, "Invalid producer count: %s\n", arg); argp_usage(state); } break; case 'c': env.consumer_cnt = strtol(arg, NULL, 10); - if (env.consumer_cnt <= 0) { + if (env.consumer_cnt < 0) { fprintf(stderr, "Invalid consumer count: %s\n", arg); argp_usage(state); } @@ -607,6 +607,10 @@ static void setup_benchmark(void) bench->setup(); for (i = 0; i < env.consumer_cnt; i++) { + if (!bench->consumer_thread) { + fprintf(stderr, "benchmark doesn't support consumers!\n"); + exit(1); + } err = pthread_create(&state.consumers[i], NULL, bench->consumer_thread, (void *)(long)i); if (err) { @@ -626,6 +630,10 @@ static void setup_benchmark(void) env.prod_cpus.next_cpu = env.cons_cpus.next_cpu; for (i = 0; i < env.producer_cnt; i++) { + if (!bench->producer_thread) { + fprintf(stderr, "benchmark doesn't support producers!\n"); + exit(1); + } err = pthread_create(&state.producers[i], NULL, bench->producer_thread, (void *)(long)i); if (err) { -- 2.34.1