Runtime.getRuntime.exec 139 (SIGSEGV) from Java for C programs

Question

I'm creating a Java program to run C executables, using Runtime.getRuntime.exec(String command) method, but sometimes it returns exitValue=139(SIGSEGV) even if C programs work fine when I run them from terminal or Eclipse.

What could be the problem?

Process pro = Runtime.getRuntime().exec("./cExecutable 10");

System.out.println(command + " exitValue=" + pro.exitValue());

If it can be useful, I'm using Ubuntu 18.04.

Important, I also noticed that it happens most frequently when executable output has more than 600 lines.

In fact outputs of my programs are very large

Answer 1

Java process launcher is can freeze if the STDERR/OUT streams of the sub-process are not read, but I've never seen this cause SIGSEGV in the sub-process so this may not help you.

However as you say your apps write a lot of data then it may be worth fixing your launcher to consume the output streams. ProcessBuilder gives better control over the launch than Runtime.getRuntime , this example writes STDERR/OUT streams to files so you don't need to consume in background threads:

String[] cmd = new String[] {"cExecutable","10"};
ProcessBuilder pb = new ProcessBuilder(cmd);

// Set up STDOUT:
Path tmpdir = Path.of(System.getProperty("java.io.tmpdir"));
Path fn = Path.of(cmd[0]).getFileName();
Path out = tmpdir.resolve(fn+"-stdout.log");
pb.redirectOutput(out.toFile());

// EITHER: Set up STDERR:
Path err = tmpdir.resolve(fn+"-stderr.log");
pb.redirectError(err.toFile());
// OR: join err to std with
// pb.redirectErrorStream(true);

// Launch and wait:
Process p = pb.start();
long pid = p.pid();
System.out.println("started PID "+pid);

// could close STDIN to signal end of input
p.getOutputStream().close();

int rc = p.waitFor();

System.out.println("Exit PID "+pid+": RC "+rc +" => "+(rc == 0 ? "OK": "**** ERROR ****"));
System.out.println("STDOUT: \""+Files.readString(out)+'"');
System.out.println("STDERR: \""+Files.readString(err)+'"');