When using the remove sysfs file, the device configuration is set to -1 (unconfigured). This eventually unbind drivers with the bandwidth_mutex held. Some drivers may call functions that hold said mutex, like usb_reset_device. This is the case for rtl8187, for example. This will lead to the same process holding the mutex twice, which deadlocks. Unbinding the driver before holding the bandwidth_mutex solves the problem. If any operation after that fails, drivers are not bound again. But that would be a problem anyway that the user may solve resetting the device configuration to one that works, just like he would need to do in most other failure cases. --- NOTE: Not signed-off yet, because I'm waiting for some review. Thanks! --- drivers/usb/core/message.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index fd4c36e..fe6b9e8 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1724,6 +1724,12 @@ free_interfaces: if (ret) goto free_interfaces; + /* if it's already configured, clear out old state first. + * getting rid of old interfaces means unbinding their drivers. + */ + if (dev->state != USB_STATE_ADDRESS) + usb_disable_device(dev, 1); /* Skip ep0 */ + /* Make sure we have bandwidth (and available HCD resources) for this * configuration. Remove endpoints from the schedule if we're dropping * this configuration to set configuration 0. After this point, the @@ -1738,12 +1744,6 @@ free_interfaces: goto free_interfaces; } - /* if it's already configured, clear out old state first. - * getting rid of old interfaces means unbinding their drivers. - */ - if (dev->state != USB_STATE_ADDRESS) - usb_disable_device(dev, 1); /* Skip ep0 */ - /* Get rid of pending async Set-Config requests for this device */ cancel_async_set_config(dev); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
