Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757364AbZJBIr7 (ORCPT ); Fri, 2 Oct 2009 04:47:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757356AbZJBIr6 (ORCPT ); Fri, 2 Oct 2009 04:47:58 -0400 Received: from ey-out-2122.google.com ([74.125.78.26]:5632 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753555AbZJBIr4 (ORCPT ); Fri, 2 Oct 2009 04:47:56 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=nw7q1vnKU4/4grf1OgMIoJT5tXoJPU7UWW3pUpU6/WZkUjsciWbUEn6FVVXxzBcvCB xsdBH0CXvlx9LuhR95vZm4OoJEa5dCXlAJzJr2LiwnFdnCVqljWItwLgFnEKsE/1qERS ExtdC2z8JaIrEVKSj7CC9UM8khBpORcfgOz0A= Date: Fri, 2 Oct 2009 10:47:55 +0200 From: Johan Hovold To: "Eric W. Biederman" , Greg Kroah-Hartman , Alan Cox Cc: Johan Hovold , Michael Trimarchi , Oliver Neukum , linux-usb@vger.kernel.org, Alan Cox , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] USB: ftdi_sio: Remove tty->low_latency. Message-ID: <20091002084755.GA7382@localhost> References: <20090924154023.GA27480@localhost> <200909242103.48562.oliver@neukum.org> <20090924202107.4730f2af@lxorguk.ukuu.org.uk> <20090924211459.GB27963@localhost> <4ABD020B.4040901@gandalf.sssup.it> <20090929145514.GF2152@localhost> <20090929235232.1ae6c63b@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1228 Lines: 34 On Thu, Oct 01, 2009 at 07:52:21PM -0700, Eric W. Biederman wrote: > Alan Cox writes: > > >> As it stands today ftdi_sio does indeed call tty_flip_buffer_push from > >> interrupt context with low_latency set and that is obviously incorrect, > >> right? > > > > It seems to do it from a work queue - or did I miss a case ? > > ftdi_sio crash quite regularly for me with 2.6.31. > > With a bunch of nasties like: > BUG: scheduling while atomic: swapper/0/0x00010000 > bad: scheduling from the idle thread! It's the same problem. Greg, can't we apply the patch for stable at least? Then we can massage ftdi_sio into actually using the work queue for doing _all_ processing in the meantime if deemed necessary. Alan, did you have time to look at it? Are there any reasons for wanting to keep low_latency in ftdi_sio when it was removed from all other drivers processing in interrupt context (without doing work queue re-implementations)? Thanks, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/