From 620cc1df7f260855bfa05f56483ced4be702d57b Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Wed, 31 Oct 2012 09:16:46 -0700 Subject: [PATCH] iscsi-target: Fix missed wakeup race in TX thread commit d5627acba9ae584cf4928af19f7ddf5f6837de32 upstream. The sleeping code in iscsi_target_tx_thread() is susceptible to the classic missed wakeup race: - TX thread finishes handle_immediate_queue() and handle_response_queue(), thinks both queues are empty. - Another thread adds a queue entry and does wake_up_process(), which does nothing because the TX thread is still awake. - TX thread does schedule_timeout() and sleeps forever. In practice this can kill an iSCSI connection if for example an initiator does single-threaded writes and the target misses the wakeup window when queueing an R2T; in this case the connection will be stuck until the initiator loses patience and does some task management operation (or kills the connection entirely). Fix this by converting to wait_event_interruptible(), which does not suffer from this sort of race. Signed-off-by: Roland Dreier Cc: Andy Grover Cc: Hannes Reinecke Cc: Christoph Hellwig Signed-off-by: Nicholas Bellinger Signed-off-by: Ben Hutchings --- Reading git-format-patch failed