From 310d3d314be7f0a84011ebdc4bdccbcae9755a87 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Fri, 5 Feb 2016 14:51:36 -0800 Subject: target: Fix race with SCF_SEND_DELAYED_TAS handling This patch fixes a race between setting of SCF_SEND_DELAYED_TAS in transport_send_task_abort(), and check of the same bit in transport_check_aborted_status(). It adds a __transport_check_aborted_status() version that is used by target_execute_cmd() when se_cmd->t_state_lock is held, and a transport_check_aborted_status() wrapper for all other existing callers. Also, it handles the case where the check happens before transport_send_task_abort() gets called. For this, go ahead and set SCF_SEND_DELAYED_TAS early when necessary, and have transport_send_task_abort() send the abort. Cc: Quinn Tran Cc: Himanshu Madhani Cc: Sagi Grimberg Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Andy Grover Cc: Mike Christie Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_transport.c | 53 ++++++++++++++++++++++++++-------- 1 file changed, 41 insertions(+), 12 deletions(-) (limited to 'drivers/target') diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 3441b159e306..2e0b23a3d5c4 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1858,19 +1858,21 @@ static bool target_handle_task_attr(struct se_cmd *cmd) return true; } +static int __transport_check_aborted_status(struct se_cmd *, int); + void target_execute_cmd(struct se_cmd *cmd) { - /* - * If the received CDB has aleady been aborted stop processing it here. - */ - if (transport_check_aborted_status(cmd, 1)) - return; - /* * Determine if frontend context caller is requesting the stopping of * this command for frontend exceptions. + * + * If the received CDB has aleady been aborted stop processing it here. */ spin_lock_irq(&cmd->t_state_lock); + if (__transport_check_aborted_status(cmd, 1)) { + spin_unlock_irq(&cmd->t_state_lock); + return; + } if (cmd->transport_state & CMD_T_STOP) { pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n", __func__, __LINE__, cmd->tag); @@ -2911,28 +2913,49 @@ transport_send_check_condition_and_sense(struct se_cmd *cmd, } EXPORT_SYMBOL(transport_send_check_condition_and_sense); -int transport_check_aborted_status(struct se_cmd *cmd, int send_status) +static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status) + __releases(&cmd->t_state_lock) + __acquires(&cmd->t_state_lock) { + assert_spin_locked(&cmd->t_state_lock); + WARN_ON_ONCE(!irqs_disabled()); + if (!(cmd->transport_state & CMD_T_ABORTED)) return 0; - /* * If cmd has been aborted but either no status is to be sent or it has * already been sent, just return */ - if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) + if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) { + if (send_status) + cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS; return 1; + } - pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB: 0x%02x ITT: 0x%08llx\n", - cmd->t_task_cdb[0], cmd->tag); + pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:" + " 0x%02x ITT: 0x%08llx\n", cmd->t_task_cdb[0], cmd->tag); cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS; cmd->scsi_status = SAM_STAT_TASK_ABORTED; trace_target_cmd_complete(cmd); + + spin_unlock_irq(&cmd->t_state_lock); cmd->se_tfo->queue_status(cmd); + spin_lock_irq(&cmd->t_state_lock); return 1; } + +int transport_check_aborted_status(struct se_cmd *cmd, int send_status) +{ + int ret; + + spin_lock_irq(&cmd->t_state_lock); + ret = __transport_check_aborted_status(cmd, send_status); + spin_unlock_irq(&cmd->t_state_lock); + + return ret; +} EXPORT_SYMBOL(transport_check_aborted_status); void transport_send_task_abort(struct se_cmd *cmd) @@ -2954,11 +2977,17 @@ void transport_send_task_abort(struct se_cmd *cmd) */ if (cmd->data_direction == DMA_TO_DEVICE) { if (cmd->se_tfo->write_pending_status(cmd) != 0) { - cmd->transport_state |= CMD_T_ABORTED; + spin_lock_irqsave(&cmd->t_state_lock, flags); + if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) { + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + goto send_abort; + } cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS; + spin_unlock_irqrestore(&cmd->t_state_lock, flags); return; } } +send_abort: cmd->scsi_status = SAM_STAT_TASK_ABORTED; transport_lun_remove_cmd(cmd); -- cgit v1.2.3