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authorAlan Stern <stern@rowland.harvard.edu>2011-07-06 17:03:45 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-07-08 23:15:43 -0700
commitb8680d130d565da6eb07567bd6ff20b73f747498 (patch)
tree891d92ef660465827b837900d35f1de46db1227e
parent497bf5d2301241813317f5d66b8934ce628060a8 (diff)
USB: additional regression fix for device removal
commit ca5c485f55d326d9a23e4badd05890148aa53f74 upstream. Commit e534c5b831c8b8e9f5edee5c8a37753c808b80dc (USB: fix regression occurring during device removal) didn't go far enough. It failed to take into account that when a driver claims multiple interfaces, it may release them all at the same time. As a result, some interfaces can get released before they are unregistered, and we deadlock trying to acquire the bandwidth_mutex that we already own. This patch (asl478) handles this case by setting the "unregistering" flag on all the interfaces before removing any of them. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: √Čric Piel <eric.piel@tremplin-utc.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/core/message.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index e0719b4ee189..0b5ec234c787 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1147,6 +1147,14 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
* any drivers bound to them (a key side effect)
*/
if (dev->actconfig) {
+ /*
+ * FIXME: In order to avoid self-deadlock involving the
+ * bandwidth_mutex, we have to mark all the interfaces
+ * before unregistering any of them.
+ */
+ for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++)
+ dev->actconfig->interface[i]->unregistering = 1;
+
for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
struct usb_interface *interface;
@@ -1156,7 +1164,6 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
continue;
dev_dbg(&dev->dev, "unregistering interface %s\n",
dev_name(&interface->dev));
- interface->unregistering = 1;
remove_intf_ep_devs(interface);
device_del(&interface->dev);
}