Re: linux-next crash in xhci_add_ep_to_interval

[Dan Williams]

On Thu, 2014-06-05 at 13:29 -0400, Valdis.Kletnieks@xxxxxx wrote:
> On Thu, 05 Jun 2014 09:35:48 -0700, Dan Williams said:
> 
> > Actually, on second look I bet xhci_alloc_tt_info() is being called
> > while hdev->maxchild is not set.  Let me throw together a debug
> > patch...
> 
> Sure, no problem - just let me know what variant of linux-next you
> want it applied against. :)

This should apply to -next.  Use "git am -c", but I have attached it for
convenience as well.  Boots for me, but more importantly does it boot
for you :-).

8<------
Subject: usb: fix ->update_hub_device() vs hdev->maxchild

From: Dan Williams <dan.j.williams@xxxxxxxxx>

Commit d8521afe3586 "usb: assign default peer ports for root hubs"
delayed marking a hub valid (set hdev->maxchild) until it had been fully
configured and to enable the publishing of valid hubs to be serialized
by usb_port_peer_mutex.

However, xhci_update_hub_device() in some cases depends on
hdev->maxchild already being set.  Do the minimal fix and move it after
the setting of hdev->maxchild.

Cc: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Reported-by: Valdis Kletnieks <Valdis.Kletnieks@xxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/usb/core/hub.c |   24 ++++++++++++------------
 1 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index db6287025c06..971d95745e2a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1526,18 +1526,6 @@ static int hub_configure(struct usb_hub *hub,
 		dev_dbg(hub_dev, "%umA bus power budget for each child\n",
 				hub->mA_per_port);
 
-	/* Update the HCD's internal representation of this hub before khubd
-	 * starts getting port status changes for devices under the hub.
-	 */
-	if (hcd->driver->update_hub_device) {
-		ret = hcd->driver->update_hub_device(hcd, hdev,
-				&hub->tt, GFP_KERNEL);
-		if (ret < 0) {
-			message = "can't update HCD hub info";
-			goto fail;
-		}
-	}
-
 	ret = hub_hub_status(hub, &hubstatus, &hubchange);
 	if (ret < 0) {
 		message = "can't get hub status";
@@ -1593,6 +1581,18 @@ static int hub_configure(struct usb_hub *hub,
 	if (ret < 0)
 		goto fail;
 
+	/* Update the HCD's internal representation of this hub before khubd
+	 * starts getting port status changes for devices under the hub.
+	 */
+	if (hcd->driver->update_hub_device) {
+		ret = hcd->driver->update_hub_device(hcd, hdev,
+				&hub->tt, GFP_KERNEL);
+		if (ret < 0) {
+			message = "can't update HCD hub info";
+			goto fail;
+		}
+	}
+
 	usb_hub_adjust_deviceremovable(hdev, hub->descriptor);
 
 	hub_activate(hub, HUB_INIT);

usb: fix ->update_hub_device() vs hdev->maxchild

From: Dan Williams <dan.j.williams@xxxxxxxxx>

Commit d8521afe3586 "usb: assign default peer ports for root hubs"
delayed marking a hub valid (set hdev->maxchild) until it had been fully
configured and to enable the publishing of valid hubs to be serialized
by usb_port_peer_mutex.

However, xhci_update_hub_device() in some cases depends on
hdev->maxchild already being set.  Do the minimal fix and move it after
the setting of hdev->maxchild.

Cc: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Reported-by: Valdis Kletnieks <Valdis.Kletnieks@xxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/usb/core/hub.c |   24 ++++++++++++------------
 1 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index db6287025c06..971d95745e2a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1526,18 +1526,6 @@ static int hub_configure(struct usb_hub *hub,
 		dev_dbg(hub_dev, "%umA bus power budget for each child\n",
 				hub->mA_per_port);
 
-	/* Update the HCD's internal representation of this hub before khubd
-	 * starts getting port status changes for devices under the hub.
-	 */
-	if (hcd->driver->update_hub_device) {
-		ret = hcd->driver->update_hub_device(hcd, hdev,
-				&hub->tt, GFP_KERNEL);
-		if (ret < 0) {
-			message = "can't update HCD hub info";
-			goto fail;
-		}
-	}
-
 	ret = hub_hub_status(hub, &hubstatus, &hubchange);
 	if (ret < 0) {
 		message = "can't get hub status";
@@ -1593,6 +1581,18 @@ static int hub_configure(struct usb_hub *hub,
 	if (ret < 0)
 		goto fail;
 
+	/* Update the HCD's internal representation of this hub before khubd
+	 * starts getting port status changes for devices under the hub.
+	 */
+	if (hcd->driver->update_hub_device) {
+		ret = hcd->driver->update_hub_device(hcd, hdev,
+				&hub->tt, GFP_KERNEL);
+		if (ret < 0) {
+			message = "can't update HCD hub info";
+			goto fail;
+		}
+	}
+
 	usb_hub_adjust_deviceremovable(hdev, hub->descriptor);
 
 	hub_activate(hub, HUB_INIT);