Hans Petter Selasky
714ed5b27b
Deadlock condition: The return value of TDQ_LOCKPTR(td) is the same for two threads. 1) The first thread signals a wakeup while keeping the rcu_read_lock(). This invokes sched_add() which in turn will try to lock TDQ_LOCK(). 2) The second thread is calling synchronize_rcu() calling mi_switch() over and over again trying to yield(). This prevents the first thread from running and releasing the RCU reader lock. Solution: Release the thread lock while yielding to allow other threads to acquire the lock pointed to by TDQ_LOCKPTR(td). Found by: KrishnamRaju ErapaRaju <Krishna2@chelsio.com> MFC after: 1 week Sponsored by: Mellanox Technologies
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