The patch below does not apply to the 3.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 310d3d314be7f0a84011ebdc4bdccbcae9755a87 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Date: Fri, 5 Feb 2016 14:51:36 -0800
Subject: [PATCH] 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 <quinn.tran@xxxxxxxxxx>
Cc: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Andy Grover <agrover@xxxxxxxxxx>
Cc: Mike Christie <mchristi@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.10+
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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);
--
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