linux-kernel - [PATCH 4.14 32/45] nvme_fc: fix ctrl create failures racing with workq items

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Message-Id: <20181011152510.306498191@linuxfoundation.org>
Date:   Thu, 11 Oct 2018 17:39:59 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, James Smart <james.smart@...adcom.com>,
        Keith Busch <keith.busch@...el.com>,
        Jens Axboe <axboe@...nel.dk>,
        Amit Pundir <amit.pundir@...aro.org>
Subject: [PATCH 4.14 32/45] nvme_fc: fix ctrl create failures racing with workq items

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Smart <jsmart2021@...il.com>

commit cf25809bec2c7df4b45df5b2196845d9a4a3c89b upstream.

If there are errors during initial controller create, the transport
will teardown the partially initialized controller struct and free
the ctlr memory.  Trouble is - most of those errors can occur due
to asynchronous events happening such io timeouts and subsystem
connectivity failures. Those failures invoke async workq items to
reset the controller and attempt reconnect.  Those may be in progress
as the main thread frees the ctrl memory, resulting in NULL ptr oops.

Prevent this from happening by having the main ctrl failure thread
changing state to DELETING followed by synchronously cancelling any
pending queued work item. The change of state will prevent the
scheduling of resets or reconnect events.

Signed-off-by: James Smart <james.smart@...adcom.com>
Signed-off-by: Keith Busch <keith.busch@...el.com>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Amit Pundir <amit.pundir@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/nvme/host/fc.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -2868,6 +2868,10 @@ nvme_fc_init_ctrl(struct device *dev, st
 	}

 	if (ret) {
+		nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_DELETING);
+		cancel_work_sync(&ctrl->ctrl.reset_work);
+		cancel_delayed_work_sync(&ctrl->connect_work);
+
 		/* couldn't schedule retry - fail out */
 		dev_err(ctrl->ctrl.device,
 			"NVME-FC{%d}: Connect retry failed\n", ctrl->cnum);