Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965158AbcCIXnx (ORCPT ); Wed, 9 Mar 2016 18:43:53 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:40807 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934616AbcCIXQh (ORCPT ); Wed, 9 Mar 2016 18:16:37 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Quinn Tran , Himanshu Madhani , Sagi Grimberg , Christoph Hellwig , Hannes Reinecke , Andy Grover , Mike Christie , Nicholas Bellinger , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 047/138] target: Fix race with SCF_SEND_DELAYED_TAS handling Date: Wed, 9 Mar 2016 15:12:54 -0800 Message-Id: <1457565265-15195-48-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457565265-15195-1-git-send-email-kamal@canonical.com> References: <1457565265-15195-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4873 Lines: 145 3.13.11-ckt36 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Nicholas Bellinger commit 310d3d314be7f0a84011ebdc4bdccbcae9755a87 upstream. 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 Signed-off-by: Nicholas Bellinger Signed-off-by: Kamal Mostafa --- drivers/target/target_core_transport.c | 54 ++++++++++++++++++++++++++-------- 1 file changed, 42 insertions(+), 12 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 09268ad..8430a15 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1716,19 +1716,21 @@ 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%08x\n", __func__, __LINE__, @@ -2811,8 +2813,13 @@ after_reason: } 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; @@ -2820,19 +2827,37 @@ int transport_check_aborted_status(struct se_cmd *cmd, int send_status) * 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%08x\n", - cmd->t_task_cdb[0], cmd->se_tfo->get_task_tag(cmd)); + pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:" + " 0x%02x ITT: 0x%08x\n", cmd->t_task_cdb[0], + cmd->se_tfo->get_task_tag(cmd)); 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) @@ -2854,12 +2879,17 @@ 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; - smp_mb__after_atomic_inc(); + spin_unlock_irqrestore(&cmd->t_state_lock, flags); return; } } +send_abort: cmd->scsi_status = SAM_STAT_TASK_ABORTED; transport_lun_remove_cmd(cmd); -- 2.7.0