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authorJames Smart <jsmart2021@gmail.com>2018-11-27 17:04:44 -0800
committerChristoph Hellwig <hch@lst.de>2018-12-07 07:11:11 -0800
commit86880d646122240596d6719b642fee3213239994 (patch)
tree57b804557708872df882b552e168d484ca082f36
parentba7aeae5539c7a7cccc4cf07a2bc61281a93c50e (diff)
nvme: validate controller state before rescheduling keep alive
Delete operations are seeing NULL pointer references in call_timer_fn. Tracking these back, the timer appears to be the keep alive timer. nvme_keep_alive_work() which is tied to the timer that is cancelled by nvme_stop_keep_alive(), simply starts the keep alive io but doesn't wait for it's completion. So nvme_stop_keep_alive() only stops a timer when it's pending. When a keep alive is in flight, there is no timer running and the nvme_stop_keep_alive() will have no affect on the keep alive io. Thus, if the io completes successfully, the keep alive timer will be rescheduled. In the failure case, delete is called, the controller state is changed, the nvme_stop_keep_alive() is called while the io is outstanding, and the delete path continues on. The keep alive happens to successfully complete before the delete paths mark it as aborted as part of the queue termination, so the timer is restarted. The delete paths then tear down the controller, and later on the timer code fires and the timer entry is now corrupt. Fix by validating the controller state before rescheduling the keep alive. Testing with the fix has confirmed the condition above was hit. Signed-off-by: James Smart <jsmart2021@gmail.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de>
-rw-r--r--drivers/nvme/host/core.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 3cf1b773158e..962012135b62 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -831,6 +831,8 @@ static int nvme_submit_user_cmd(struct request_queue *q,
static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
{
struct nvme_ctrl *ctrl = rq->end_io_data;
+ unsigned long flags;
+ bool startka = false;
blk_mq_free_request(rq);
@@ -841,7 +843,13 @@ static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
return;
}
- schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
+ spin_lock_irqsave(&ctrl->lock, flags);
+ if (ctrl->state == NVME_CTRL_LIVE ||
+ ctrl->state == NVME_CTRL_CONNECTING)
+ startka = true;
+ spin_unlock_irqrestore(&ctrl->lock, flags);
+ if (startka)
+ schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
}
static int nvme_keep_alive(struct nvme_ctrl *ctrl)