RFR: 8220175: serviceability/dcmd/framework/VMVersionTest.java fails with a timeout

[serguei.spitsyn at oracle.com]

Hi Daniil,

It looks good to me.

Thanks,
Serguei


On 6/19/19 21:02, Daniil Titov wrote:
> Please review the change that fixes an intermittent failure of serviceability/dcmd/framework/* tests on Linux platform.
>
> The problem here is that get_namespace_pid() method, that is called by mmap_attach_shared () that in turn is called by PerfMemory::attach(),
> tries to read the namespace pid information from /proc/<pid>/status file. However, it doesn't check that the error indicator associated with
> stream is set that results in the endless  loop (lines 664-677) if the process terminates after /proc/<pid>/status was opened (line 659)
> and checked for null (line 661).
>
>    658	  snprintf(fname, sizeof(fname), "/proc/%d/status", vmid);
>     659	  FILE *fp = fopen(fname, "r");
>     660	
>     661	  if (fp) {
>     662	    int pid, nspid;
>     663	    int ret;
>     664	    while (!feof(fp)) {
>     665	      ret = fscanf(fp, "NSpid: %d %d", &pid, &nspid);
>     666	      if (ret == 1) {
>     667	        break;
>     668	      }
>     669	      if (ret == 2) {
>     670	        retpid = nspid;
>     671	        break;
>     672	      }
>     673	      for (;;) {
>     674	        int ch = fgetc(fp);
>     675	        if (ch == EOF || ch == (int)'\n') break;
>     676	      }
>     677	    }
>     678	    fclose(fp);
>     679	  }
>
> The fix adds the check for the error indicator to ensure that the "while" loop terminates properly if the file no longer exists.
>
> Issues [3] and [4] have the same cause and will be closed as duplicates of this issue.
>
> Testing: Mach5 hotspot_serviceability tests succeeded, tier1,tier2, and tier3 tests are in progress.
>
> [1] Webrev: http://cr.openjdk.java.net/~dtitov/8220175/webrev.01/
> [2] Bug: https://bugs.openjdk.java.net/browse/JDK-8220175
> [3] https://bugs.openjdk.java.net/browse/JDK-8223600
> [4] https://bugs.openjdk.java.net/browse/JDK-8217351
>
> Thanks!
> -Daniil
>
>