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  1. JDK
  2. JDK-8259943

FileDescriptor.close0 does not handle EINTR

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 8u271, 11.0.9, 15.0.1, 17
    • Fix Version/s: 17
    • Component/s: core-libs
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b07
    • OS:
      linux, os_x

      Description

      The bug is similar to JDK-8237858.

      In fileDescriptorClose(), if close() returns -1, IOException is thrown.
      However, when profiling application with a signal-based mechanism, close() can be interrupted by a signal and return -1 with errno=EINTR. This happens when the underlying file system is a network file system, e.g. CIFS.

      The problem was originally reported against async-profiler:
      https://github.com/jvm-profiling-tools/async-profiler/issues/384

      I can always reproduce the bug with the following simple program:

      public class CifsBug {

          public static void main(String[] args) throws Exception {
              byte[] buf = new byte[65536];
              ThreadLocalRandom.current().nextBytes(buf);

              for (int fileId = 0; fileId < 1000; fileId++) {
                  System.out.println("Writing " + fileId);
                  try (FileOutputStream out = new FileOutputStream("/mnt/cifs/tmp" + fileId + ".tmp")) {
                      out.write(buf, 0, buf.length);
                      System.out.println("Closing " + fileId);
                  }
              }
          }
      }

      When I run it with -agentlib:asyncProfiler=start,event=cpu,interval=1ms the program eventually throws IOException:

      Exception in thread "main" java.io.IOException: Interrupted system call
              at java.base/java.io.FileDescriptor.close0(Native Method)
              at java.base/java.io.FileDescriptor.close(FileDescriptor.java:297)
              at java.base/java.io.FileOutputStream$1.close(FileOutputStream.java:390)
              at java.base/java.io.FileDescriptor.closeAll(FileDescriptor.java:355)
              at java.base/java.io.FileOutputStream.close(FileOutputStream.java:388)
              at CifsBug.main(CifsBug.java:15)

      Linux man page for close() explicitly mentions that close() may return errno=EINTR: https://man7.org/linux/man-pages/man2/close.2.html
      So, JDK should handle EINTR in fileDescriptorClose() and silently ignore it on Linux, just like UnixNativeDispatcher_close0 already does.

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              Assignee:
              bpb Brian Burkhalter
              Reporter:
              apangin Andrei Pangin
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                Created:
                Updated:
                Resolved: