[QPID-8206] [linearstore] Deadlock possible in InactivityFireEvent if fire() is called at the same time as cancel()

• Type: Bug
• Status: Reviewable
• Priority: Major
• Resolution: Unresolved
• Component/s: C++ Broker
• Assignee: Kim van der Riet
• Reporter: Kim van der Riet
• Created: 07/Jun/18 17:09
• Updated: 08/Jun/18 14:24

Description

A deadlock has been observed in InactivityFireEvent if InactivityFireEvent::fire() triggered by the timer occurs at almost the same time as InactivityFireEvent::cancel() on another thread, and which occurs if the queue is deleted.

The mutex InactivityFireEvent::_ifeStateLock becomes deadlocked if the thread calling cancel() obtains the lock, but a fire event is imminent. The fire() call will then be blocked on this mutex. However, cancel cannot complete until fire competes owing to the sys::Time Monitor which waits for all fires to complete before allowing the cancel to occur.