sigusr1_received 4 tools/testing/selftests/bpf/prog_tests/send_signal.c static volatile int sigusr1_received = 0; sigusr1_received 8 tools/testing/selftests/bpf/prog_tests/send_signal.c sigusr1_received++; sigusr1_received 60 tools/testing/selftests/bpf/prog_tests/send_signal.c if (sigusr1_received)