netdev - Re: [PATCH] usbnet: Activate halt interrupt endpoint before re-submit URB

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <201206201221.37211.oneukum@suse.de>
Date:	Wed, 20 Jun 2012 12:21:37 +0200
From:	Oliver Neukum <oneukum@...e.de>
To:	Ming Lei <tom.leiming@...il.com>
Cc:	Huajun Li <huajun.li.lee@...il.com>,
	David Miller <davem@...emloft.net>, stern@...land.harvard.edu,
	linux-usb@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH] usbnet: Activate halt interrupt endpoint before re-submit URB

Am Mittwoch, 20. Juni 2012, 12:15:25 schrieb Ming Lei:
> On Wed, Jun 20, 2012 at 4:58 PM, Oliver Neukum <oneukum@...e.de> wrote:
> > Am Mittwoch, 20. Juni 2012, 10:07:55 schrieb Ming Lei:
> >> BTW, maybe it is better to add below
> >>
> >>     usbnet_defer_kevent(dev, EVENT_STS_HALT);
> >>
> >> for -EPIPE returned from usb_urb_submit if it will be resent.
> >
> > Why? If it failed once it'll probably also fail the next time.
> 
> -EPIPE just means the endpoint is halted, either from usb_urb_submit
> or urb->status, so the HALT should be cleared in the situation.

It probably was halted and cleared. However that you cleared
a halt doesn't mean that the reason for stalling went away.
So you must cope with an endpoint being halted again right after
it was cleared.

> > In that case we'd need to do something more intrusive
> > like resetting the device, but that cannot be done well
> > in the generic usbnet part.
> 
> IMO, resetting is not needed for -EPIPE, but may be needed for
> -EPROTO failure.

We don't need it for a single failure, but what else would we do
if we keep getting -EPIPE?

	Regards
		Oliver

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html