[KUDU-2721] CHECK can be hit when there are gaps in present CPU numbers

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.8.0
• Fix Version/s: 1.10.0
• Labels: crash
• Environment: SLES12-SP3
• Assignee: Tim Armstrong
• Reporter: Tim Armstrong
• Created: 01/Mar/19 19:09
• Updated: 07/Mar/19 04:46
• Resolved: 07/Mar/19 04:46

Description

We saw a case where Impala is crashing in the Kudu client and it seems to be because the "present" string can have multiple ranges in it - "0-15,32-47\n" in this case. See https://github.com/apache/kudu/blob/148a0c7bec6554724339a2235cbd723fb74be339/src/kudu/gutil/sysinfo.cc#L177

I've attached a small test program based on the code illustrating that the assert gets hit.

I think we should figure out all of the possible formats for the present string and make sure we handle them. Or figure out a different way to get equivalent info.

A workaround for the case that we saw was to disable hyperthreading, which changed the string to being a single range.

Issue Links

• causes: IMPALA-8277 CHECK can be hit when there are gaps in present CPU numbers (KUDU-2721)
• is related to: KUDU-2730 ReadMaxCpuIndex doesn't include possible hotplugged CPUs