Details
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Bug
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Status: Patch Available
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Major
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Resolution: Unresolved
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2.9.0, 3.0.0, 3.1.0, 2.10.0, 3.2.0, 3.3.0
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None
Description
This is a potential bug may impact all open premmption cluster.In our current version with preemption enabled, the capacityScheduler will call the refreshQueue method of the PreemptionManager when it refreshQueue. This process hold the preemptionManager write lock and require csqueue read lock.Meanwhile,ParentQueue.canAssignToThisQueue will hold csqueue readLock and require PreemptionManager ReadLock.
There is a possibility of deadlock at this time.Because readlock has one rule on unfair policy, when a lock is already occupied by a read lock and the first request in the lock competition queue is a write lock request,other read lock requests cann‘t acquire the lock.
So the potential deadlock is:
CapacityScheduler.refreshQueue: hold: PremmptionManager.writeLock
require: csqueue.readLock
CapacityScheduler.schedule: hold: csqueue.readLock
require: PremmptionManager.readLock
other thread(completeContainer,release Resource,etc.): require: csqueue.writeLock
The jstack logs at the time were as follows
