patch "mei: fix NULL dereferencing during FW initiated disconnection" added to char-misc-testing

This is a note to let you know that I've just added the patch titled

mei: fix NULL dereferencing during FW initiated disconnection

to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the char-misc-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From: Alexander Usyskin <[email protected]>
Date: Sun, 17 Apr 2016 12:16:03 -0400
Subject: mei: fix NULL dereferencing during FW initiated disconnection

In the case when disconnection is initiated from the FW the driver is flushing items from the write control list while iterating over it:

mei_irq_write_handler()
list_for_each_entry_safe(ctrl_wr_list) <-- outer loop
mei_cl_irq_disconnect_rsp()
mei_cl_set_disconnected()
mei_io_list_flush(ctrl_wr_list) <-- destorying list

We move the list flushing to the completion routine.

---
 drivers/misc/mei/client.c    | 4 ++++
 drivers/misc/mei/hbm.c       | 3 +--
 drivers/misc/mei/interrupt.c | 5 +----
 3 files changed, 6 insertions(+), 6 deletions(-)

index bab17e4197b6..09f5280fa021 100644
@@ -1767,6 +1767,10 @@ void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb)
 			wake_up(&cl->wait);
 
 		break;
+	case MEI_FOP_DISCONNECT_RSP:
+		mei_io_cb_free(cb);
+		mei_cl_set_disconnected(cl);
+		break;
 	default:
 		BUG_ON(0);
 	}

index 5eaa4638e824..5aa606c8a827 100644
@@ -877,8 +877,7 @@ static int mei_hbm_fw_disconnect_req(struct mei_device *dev,
 		cb = mei_io_cb_init(cl, MEI_FOP_DISCONNECT_RSP, NULL);
 		if (!cb)
 			return -ENOMEM;
-		cl_dbg(dev, cl, "add disconnect response as first\n");
-		list_add(&cb->list, &dev->ctrl_wr_list.list);
+		list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
 	}
 	return 0;
 }

index 1e5cb1f704f8..704dc6caad6d 100644
@@ -194,10 +194,7 @@ static int mei_cl_irq_disconnect_rsp(struct mei_cl *cl, struct mei_cl_cb *cb,
 		return -EMSGSIZE;
 
 	ret = mei_hbm_cl_disconnect_rsp(dev, cl);
-	mei_cl_set_disconnected(cl);
-	mei_io_cb_free(cb);
-	mei_me_cl_put(cl->me_cl);
-	cl->me_cl = NULL;
+	list_move_tail(&cb->list, &cmpl_list->list);
 
 	return ret;
 }

2.8.0