3.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <n...@linux-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.t...@qlogic.com>
Cc: Himanshu Madhani <himanshu.madh...@qlogic.com>
Cc: Sagi Grimberg <sa...@mellanox.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Hannes Reinecke <h...@suse.de>
Cc: Andy Grover <agro...@redhat.com>
Cc: Mike Christie <mchri...@redhat.com>
Cc: sta...@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <n...@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/target/target_core_tmr.c | 22 +++++++++++++++++++++-
drivers/target/target_core_transport.c | 17 +++++++++++++++++
2 files changed, 38 insertions(+), 1 deletion(-)
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -76,7 +76,7 @@ void core_tmr_release_req(
}
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);
kfree(tmr);
@@ -176,9 +176,11 @@ 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..
@@ -204,17 +206,31 @@ 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);
@@ -228,7 +244,11 @@ 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->se_sess, cmd);
}
}
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2895,8 +2895,17 @@ static void target_tmr_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);
@@ -2924,9 +2933,17 @@ static void target_tmr_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);
}
