From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752994AbZHTBRM (ORCPT ); Wed, 19 Aug 2009 21:17:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752319AbZHTBRL (ORCPT ); Wed, 19 Aug 2009 21:17:11 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:46536 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752194AbZHTBRK (ORCPT ); Wed, 19 Aug 2009 21:17:10 -0400 Date: Wed, 19 Aug 2009 21:17:08 -0400 From: Kyle McMartin To: Joerg Roedel Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, mchehab@infradead.org Subject: [PATCH] dma-debug: fix check_unmap null pointer dereference Message-ID: <20090820011708.GP25206@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kyle McMartin While it's debatable whether or not a NULL device argument to the DMA API functions is valid... since it certainly isn't valid on devices with an IOMMU... dma-debug really shouldn't be dereferencing null pointers either. Guard against that in err_printk and the driver_filter functions. A Fedora rawhide user was seeing this in one of the dvb drivers resulting in an oops on boot. Signed-off-by: Kyle McMartin --- A patch has been sent for testing to the driver, but I feel the dma debugging support should be fixed as well. (There's still a pile of legacy garbage in the kernel passing null pointers to dma_{alloc,free}_*. :( regards, Kyle diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 65b0d99..58a9f9f 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -156,9 +156,13 @@ static bool driver_filter(struct device *dev) return true; /* driver filter on and initialized */ - if (current_driver && dev->driver == current_driver) + if (current_driver && dev && dev->driver == current_driver) return true; + /* driver filter on, but we can't filter on a NULL device... */ + if (!dev) + return false; + if (current_driver || !current_driver_name[0]) return false; @@ -183,17 +187,17 @@ static bool driver_filter(struct device *dev) return ret; } -#define err_printk(dev, entry, format, arg...) do { \ - error_count += 1; \ - if (driver_filter(dev) && \ - (show_all_errors || show_num_errors > 0)) { \ - WARN(1, "%s %s: " format, \ - dev_driver_string(dev), \ - dev_name(dev) , ## arg); \ - dump_entry_trace(entry); \ - } \ - if (!show_all_errors && show_num_errors > 0) \ - show_num_errors -= 1; \ +#define err_printk(dev, entry, format, arg...) do { \ + error_count += 1; \ + if (driver_filter(dev) && \ + (show_all_errors || show_num_errors > 0)) { \ + WARN(1, "%s %s: " format, \ + dev ? dev_driver_string(dev) : "NULL", \ + dev ? dev_name(dev) : "NULL", ## arg); \ + dump_entry_trace(entry); \ + } \ + if (!show_all_errors && show_num_errors > 0) \ + show_num_errors -= 1; \ } while (0); /*