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Message-Id: <1457391064-6660-90-git-send-email-kamal@canonical.com>
Date: Mon, 7 Mar 2016 14:48:00 -0800
From: Kamal Mostafa <kamal@...onical.com>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org,
kernel-team@...ts.ubuntu.com
Cc: Himanshu Madhani <himanshu.madhani@...gic.com>,
Sagi Grimberg <sagig@...lanox.com>,
Christoph Hellwig <hch@....de>, Hannes Reinecke <hare@...e.de>,
Andy Grover <agrover@...hat.com>,
Mike Christie <mchristi@...hat.com>,
Nicholas Bellinger <nab@...ux-iscsi.org>,
Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 4.2.y-ckt 089/273] target: Fix LUN_RESET active TMR descriptor handling
4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Nicholas Bellinger <nab@...ux-iscsi.org>
commit a6d9bb1c9605cd4f44e2d8290dc4d0e88f20292d upstream.
This patch fixes a NULL pointer se_cmd->cmd_kref < 0
refcount bug during TMR LUN_RESET with active TMRs,
triggered during se_cmd + se_tmr_req descriptor
shutdown + release via core_tmr_drain_tmr_list().
To address this bug, go ahead and obtain a local
kref_get_unless_zero(&se_cmd->cmd_kref) for active I/O
to set CMD_T_ABORTED, and transport_wait_for_tasks()
followed by the final target_put_sess_cmd() to drop
the local ->cmd_kref.
Also add two new checks within target_tmr_work() to
avoid CMD_T_ABORTED -> TFO->queue_tm_rsp() callbacks
ahead of invoking the backend -> fabric put in
transport_cmd_check_stop_to_fabric().
For good measure, also change core_tmr_release_req()
to use list_del_init() ahead of se_tmr_req memory
free.
Reviewed-by: Quinn Tran <quinn.tran@...gic.com>
Cc: Himanshu Madhani <himanshu.madhani@...gic.com>
Cc: Sagi Grimberg <sagig@...lanox.com>
Cc: Christoph Hellwig <hch@....de>
Cc: Hannes Reinecke <hare@...e.de>
Cc: Andy Grover <agrover@...hat.com>
Cc: Mike Christie <mchristi@...hat.com>
Signed-off-by: Nicholas Bellinger <nab@...ux-iscsi.org>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
drivers/target/target_core_tmr.c | 22 +++++++++++++++++++++-
drivers/target/target_core_transport.c | 17 +++++++++++++++++
2 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 6545df43..3e3b12e 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -68,7 +68,7 @@ void core_tmr_release_req(struct se_tmr_req *tmr)
if (dev) {
spin_lock_irqsave(&dev->se_tmr_lock, flags);
- list_del(&tmr->tmr_list);
+ list_del_init(&tmr->tmr_list);
spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
}
@@ -194,9 +194,11 @@ static void core_tmr_drain_tmr_list(
struct list_head *preempt_and_abort_list)
{
LIST_HEAD(drain_tmr_list);
+ struct se_session *sess;
struct se_tmr_req *tmr_p, *tmr_pp;
struct se_cmd *cmd;
unsigned long flags;
+ bool rc;
/*
* Release all pending and outgoing TMRs aside from the received
* LUN_RESET tmr..
@@ -222,17 +224,31 @@ static void core_tmr_drain_tmr_list(
if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
continue;
+ sess = cmd->se_sess;
+ if (WARN_ON_ONCE(!sess))
+ continue;
+
+ spin_lock(&sess->sess_cmd_lock);
spin_lock(&cmd->t_state_lock);
if (!(cmd->transport_state & CMD_T_ACTIVE)) {
spin_unlock(&cmd->t_state_lock);
+ spin_unlock(&sess->sess_cmd_lock);
continue;
}
if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
spin_unlock(&cmd->t_state_lock);
+ spin_unlock(&sess->sess_cmd_lock);
continue;
}
+ cmd->transport_state |= CMD_T_ABORTED;
spin_unlock(&cmd->t_state_lock);
+ rc = kref_get_unless_zero(&cmd->cmd_kref);
+ spin_unlock(&sess->sess_cmd_lock);
+ if (!rc) {
+ printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
+ continue;
+ }
list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
}
spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
@@ -246,7 +262,11 @@ static void core_tmr_drain_tmr_list(
(preempt_and_abort_list) ? "Preempt" : "", tmr_p,
tmr_p->function, tmr_p->response, cmd->t_state);
+ cancel_work_sync(&cmd->work);
+ transport_wait_for_tasks(cmd);
+
transport_cmd_finish_abort(cmd, 1);
+ target_put_sess_cmd(cmd);
}
}
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 9361567..2e89168 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2954,8 +2954,17 @@ static void target_tmr_work(struct work_struct *work)
struct se_cmd *cmd = container_of(work, struct se_cmd, work);
struct se_device *dev = cmd->se_dev;
struct se_tmr_req *tmr = cmd->se_tmr_req;
+ unsigned long flags;
int ret;
+ spin_lock_irqsave(&cmd->t_state_lock, flags);
+ if (cmd->transport_state & CMD_T_ABORTED) {
+ tmr->response = TMR_FUNCTION_REJECTED;
+ spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+ goto check_stop;
+ }
+ spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+
switch (tmr->function) {
case TMR_ABORT_TASK:
core_tmr_abort_task(dev, tmr, cmd->se_sess);
@@ -2988,9 +2997,17 @@ static void target_tmr_work(struct work_struct *work)
break;
}
+ spin_lock_irqsave(&cmd->t_state_lock, flags);
+ if (cmd->transport_state & CMD_T_ABORTED) {
+ spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+ goto check_stop;
+ }
cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
+ spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+
cmd->se_tfo->queue_tm_rsp(cmd);
+check_stop:
transport_cmd_check_stop_to_fabric(cmd);
}
--
2.7.0
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