[HBASE-14759] Avoid using Math.abs when selecting SyncRunner in FSHLog

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.2, 1.2.0, 1.1.2, 1.3.0, 2.0.0
• Fix Version/s: 1.2.0, 1.3.0, 1.0.3, 1.1.3, 2.0.0
• Component/s: wal
• Hadoop Flags: Reviewed
• Assignee: Duo Zhang
• Reporter: Duo Zhang
• Created: 04/Nov/15 09:48
• Updated: 27/Jan/16 15:28
• Resolved: 07/Nov/15 01:36

Description

FSHLog.java

int index = Math.abs(this.syncRunnerIndex++) % this.syncRunners.length;
          try {
            this.syncRunners[index].offer(sequence, this.syncFutures, this.syncFuturesCount);
          } catch (Exception e) {
            // Should NEVER get here.
            requestLogRoll();
            this.exception = new DamagedWALException("Failed offering sync", e);
          }

Math.abs will return Integer.MIN_VALUE if you pass Integer.MIN_VALUE in since the actual absolute value of Integer.MIN_VALUE is out of range.

I think this.syncRunnerIndex++ will overflow eventually if we keep the regionserver running for enough time.