Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755533AbXJ0Ntu (ORCPT ); Sat, 27 Oct 2007 09:49:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753152AbXJ0Ntn (ORCPT ); Sat, 27 Oct 2007 09:49:43 -0400 Received: from nat-132.atmel.no ([80.232.32.132]:65284 "EHLO relay.atmel.no" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752333AbXJ0Ntm convert rfc822-to-8bit (ORCPT ); Sat, 27 Oct 2007 09:49:42 -0400 Date: Sat, 27 Oct 2007 15:49:47 +0200 From: Haavard Skinnemoen To: Dan Williams Cc: Andrew Morton , linux-kernel , Shannon Nelson Subject: Re: [PATCH] DMA: Fix broken device refcounting Message-ID: <20071027154947.6836a3d9@siona> In-Reply-To: <1193416577.9353.5.camel@dwillia2-linux.ch.intel.com> References: <1193415162504-git-send-email-hskinnemoen@atmel.com> <1193416577.9353.5.camel@dwillia2-linux.ch.intel.com> Organization: Atmel X-Mailer: Claws Mail 2.10.0 (GTK+ 2.12.0; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1044 Lines: 24 On Fri, 26 Oct 2007 09:36:17 -0700 Dan Williams wrote: > @@ -221,7 +220,6 @@ void dma_chan_cleanup(struct kref *kref) > { > struct dma_chan *chan = container_of(kref, struct dma_chan, refcount); > chan->device->device_free_chan_resources(chan); > - kref_put(&chan->device->refcount, dma_async_device_cleanup); > } > EXPORT_SYMBOL(dma_chan_cleanup); While I can't see any problems with the rest of the patch, I think this part is wrong for the same reasons removing the kref_put() from the class device cleanup function is. I don't see any constraint that guarantees that dma_chan_cleanup() will always be called before dma_dev_release(), which means that "chan" may have been freed before this function gets a chance to run. Please correct me if I'm wrong. Håvard - 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/