From: Nicholas Bellinger Date: Wed, 25 May 2016 19:25:04 +0000 (-0700) Subject: target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP X-Git-Tag: firefly_0821_release~176^2~4^2~31^2~324 X-Git-Url: http://plrg.eecs.uci.edu/git/?p=firefly-linux-kernel-4.4.55.git;a=commitdiff_plain;h=60ba156dda2c11ff7a44d78ec64abd21b9813115 target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP commit 5e2c956b8aa24d4f33ff7afef92d409eed164746 upstream. During transport_generic_free_cmd() with a concurrent TMR ABORT_TASK and shutdown CMD_T_FABRIC_STOP bit set, the caller will be blocked on se_cmd->cmd_wait_stop completion until the final kref_put() -> target_release_cmd_kref() has been invoked to call complete(). However, when ABORT_TASK is completed with FUNCTION_COMPLETE in core_tmr_abort_task(), the aborted se_cmd will have already been removed from se_sess->sess_cmd_list via list_del_init(). This results in target_release_cmd_kref() hitting the legacy list_empty() == true check, invoking ->release_cmd() but skipping complete() to wakeup se_cmd->cmd_wait_stop blocked earlier in transport_generic_free_cmd() code. To address this bug, it's safe to go ahead and drop the original list_empty() check so that fabric_stop invokes the complete() as expected, since list_del_init() can safely be used on a empty list. Cc: Mike Christie Cc: Quinn Tran Cc: Himanshu Madhani Cc: Christoph Hellwig Cc: Hannes Reinecke Tested-by: Nicholas Bellinger Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 7f4cdc82234b..93fb7c0dfa3c 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2541,12 +2541,6 @@ static void target_release_cmd_kref(struct kref *kref) bool fabric_stop; spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); - if (list_empty(&se_cmd->se_cmd_list)) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); - target_free_cmd_mem(se_cmd); - se_cmd->se_tfo->release_cmd(se_cmd); - return; - } spin_lock(&se_cmd->t_state_lock); fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP);