On 21.10.2015 22:14, Matthew R. Ochs wrote: > The process_sense() routine can perform a read capacity which > can take some time to complete. If an EEH occurs while waiting > on the read capacity, the EEH handler will wait to obtain the > context's mutex in order to put the context in an error state. > The EEH handler will sit and wait until the context is free, > but this wait can potentially last forever (deadlock) if the > scsi_execute() that performs the read capacity experiences a > timeout and calls into the reset callback. When that occurs, > the reset callback sees that the device is already being reset > and waits for the reset to complete. This leaves two threads > waiting on the other. > > To address this issue, make the context unavailable to new, > non-system owned threads and release the context while calling > into process_sense(). After returning from process_sense() the > context mutex is reacquired and the context is made available > again. The context can be safely moved to the error state if > needed during the unavailable window as no other threads will > hold its reference. > > Signed-off-by: Matthew R. Ochs <mrochs@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Manoj N. Kumar <manoj@xxxxxxxxxxxxxxxxxx> > Reviewed-by: Brian King <brking@xxxxxxxxxxxxxxxxxx> > Reviewed-by: Daniel Axtens <dja@xxxxxxxxxx> Reviewed-by: Tomas Henzl <thenzl@xxxxxxxxxx> Tomas -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
