Patent ID: 8176489

Claim:
A program storage device, comprising: program instructions stored thereon, executable by a processing device to perform operations for performing a return/rollback process for a read copy update (RCU) read-side critical section that references an RCU protected data structure, the operations comprising: determining a thread executing an RCU read-side critical section has been preempted, wherein the determining comprises determining that the thread is in an extended quiescent state; an exception handler checking a user-level state of the thread to determine whether the thread holds a lock before resuming the thread, wherein the lock for a resource is acquired in the critical section of the thread; and rolling back the thread to a beginning of the RCU read-side critical section of the thread when the user-level state indicates restart in absence of the lock held by the thread, else when the user-level state indicates the thread holds the lock, returning to a point of preemption, resuming execution and suspending checking of the user-level state for the lock.