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https://issues.apache.org/jira/browse/HBASE-20975?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Allan Yang updated HBASE-20975:
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Attachment: HBASE-20975.branch-2.0.004.patch
> Lock may not be taken while rolling back procedure
> --------------------------------------------------
>
> Key: HBASE-20975
> URL: https://issues.apache.org/jira/browse/HBASE-20975
> Project: HBase
> Issue Type: Sub-task
> Components: amv2
> Affects Versions: 2.1.0, 2.0.1
> Reporter: Allan Yang
> Assignee: Allan Yang
> Priority: Major
> Attachments: HBASE-20975.branch-2.0.001.patch,
> HBASE-20975.branch-2.0.002.patch, HBASE-20975.branch-2.0.003.patch,
> HBASE-20975.branch-2.0.004.patch
>
>
> Find this one when investigating HBASE-20921, too.
> Here is some code from executeRollback in ProcedureExecutor.java.
> {code}
> boolean reuseLock = false;
> while (stackTail --> 0) {
> final Procedure proc = subprocStack.get(stackTail);
> LockState lockState;
> //If reuseLock, then don't acquire the lock
> if (!reuseLock && (lockState = acquireLock(proc)) !=
> LockState.LOCK_ACQUIRED) {
> return lockState;
> }
> lockState = executeRollback(proc);
> boolean abortRollback = lockState != LockState.LOCK_ACQUIRED;
> abortRollback |= !isRunning() || !store.isRunning();
> //If the next procedure in the stack is the current one, then reuseLock
> = true
> reuseLock = stackTail > 0 && (subprocStack.get(stackTail - 1) == proc)
> && !abortRollback;
> //If reuseLock, don't releaseLock
> if (!reuseLock) {
> releaseLock(proc, false);
> }
> if (abortRollback) {
> return lockState;
> }
> subprocStack.remove(stackTail);
> if (proc.isYieldAfterExecutionStep(getEnvironment())) {
> return LockState.LOCK_YIELD_WAIT;
> }
> //But, here, lock is released no matter reuseLock is true or false
> if (proc != rootProc) {
> execCompletionCleanup(proc);
> }
> }
> {code}
> You can see my comments in the code above, reuseLock can cause the procedure
> executing(rollback) without a lock. Though I haven't found any bugs
> introduced by this issue, it is indeed a potential bug need to fix.
> I think we can just remove the reuseLock logic. Acquire and release lock
> every time.
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