From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olivier Sobrie Subject: Re: [PATCH 2/2] hso: fix deadlock when receiving bursts of data Date: Fri, 11 Jul 2014 11:18:03 +0200 Message-ID: <20140711091803.GA19663@hposo> References: <1404723967-24245-1-git-send-email-olivier@sobrie.be> <1404723967-24245-2-git-send-email-olivier@sobrie.be> <20140708.161633.2130069042930765600.davem@davemloft.net> <20140710142848.GA28056@hposo> <063D6719AE5E284EB5DD2968C1650D6D17270044@AcuExch.aculab.com> <20140710165003.0309924e@alan.etchedpixels.co.uk> Reply-To: Olivier Sobrie Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Laight , David Miller , "j.dumon@option.com" , "linux-usb@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" To: One Thousand Gnomes Return-path: Content-Disposition: inline In-Reply-To: <20140710165003.0309924e@alan.etchedpixels.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hi Alan and Davids, On Thu, Jul 10, 2014 at 04:50:03PM +0100, One Thousand Gnomes wrote: > On Thu, 10 Jul 2014 14:37:37 +0000 > David Laight wrote: > > > From: Olivier Sobrie > > ... > > > The function put_rxbuf_data() is called from the urb completion handler. > > > It puts the data of the urb transfer in the tty buffer with > > > tty_insert_flip_string_flags() and schedules a work queue in order to > > > push the data to the ldisc. > > > Problem is that we are in a urb completion handler so we can't wait > > > until there is room in the tty buffer. > > The tty provides the input queue, if the queue is full then just chuck > the data in the bitbucket. hso is trying to be far too clever. > > If hso is fast enough that the buffering isn't sufficient on the tty side > then we need to fix the tty buffer size. Ok I'll adapt the patch to drop the data that can't be put in the tty buffer. I test this and resend a new patch. Thanks for your help! -- Olivier