From: Alan Stern Date: Wed, 6 Jul 2011 21:03:45 +0000 (-0400) Subject: USB: additional regression fix for device removal X-Git-Tag: v2.6.39.3~1 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b8680d130d565da6eb07567bd6ff20b73f747498;p=karo-tx-linux.git 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 Tested-by: Éric Piel Signed-off-by: Greg Kroah-Hartman --- 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); }