Messages in this thread Patch in this message | | | Date | Tue, 09 Feb 2010 23:01:24 +0100 | From | Roel Kluin <> | Subject | Re: [PATCH] USB: don't read past config->interface[] if usb_control_msg() fails in usb_reset_configuration() |
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After the loop `for (i = 0; i < config->desc.bNumInterfaces; i++)' if no break occurred, i equals config->desc.bNumInterfaces. so if usb_control_msg() failed then after goto reset_old_alts we read from config->interface[config->desc.bNumInterfaces].
Reported-by: "Juha Leppanen" <juha_motorsportcom@luukku.com> Signed-off-by: Roel Kluin <roel.kluin@gmail.com> ---
>> You correctly identified a problem, but your fix is wrong -- or at >> least, it is much too complicated. The proper fix goes like this: > > /* If not, reinstate the old alternate settings */ > if (retval < 0) { > reset_old_alts: > - for (; i >= 0; i--) { > + for (i--; i >= 0; i--) { > struct usb_interface *intf = config->interface[i]; > struct usb_host_interface *alt;
Are you really sure this is better? If usb_hcd_alloc_bandwidth() fails, in the loop _before_ the reset_old_alts label, don't we still have to reinstate the old alternate settings for that usb_interface config->interface[i]? This was what my initial patch tried to do.
Alternatively usb_hcd_alloc_bandwidth() could undo what it does if an error occurs there, then I think i could be decremented.
IOW isn't this the proper fix?
Roel
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 9bc95fe..4327eab 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1489,8 +1489,10 @@ reset_old_alts: USB_REQ_SET_CONFIGURATION, 0, config->desc.bConfigurationValue, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); - if (retval < 0) + if (retval < 0) { + i--; goto reset_old_alts; + } mutex_unlock(&hcd->bandwidth_mutex); /* re-init hc/hcd interface/endpoint state */
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