From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758276AbYD0Kqi (ORCPT ); Sun, 27 Apr 2008 06:46:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752740AbYD0Kq1 (ORCPT ); Sun, 27 Apr 2008 06:46:27 -0400 Received: from mgw1.diku.dk ([130.225.96.91]:50500 "EHLO mgw1.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752248AbYD0Kq0 (ORCPT ); Sun, 27 Apr 2008 06:46:26 -0400 Date: Sun, 27 Apr 2008 12:46:22 +0200 (CEST) From: Julia Lawall To: adaplas@gmail.com, linux-fbdev-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] drivers/video/pnx4008: eliminate double free Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Julia Lawall The function framebuffer_release just calls kfree, so calling kfree subsequently on the same argument represents a double free. The comments with the definition of framebuffer_release in drivers/video/fbsysfs.c suggest that a more elaborate definition of this function is planned, such that the splitting up of framebuffer_release and kfree as done in the second instance might someday make sense, but it does not make sense now. This was found using the following semantic match. (http://www.emn.fr/x-info/coccinelle/) // @@ expression E; @@ * kfree(E); ... * framebuffer_release(E); @@ expression E; @@ * framebuffer_release(E); ... * kfree(E); // Signed-off-by: Julia Lawall --- diff -u -p a/drivers/video/pnx4008/pnxrgbfb.c b/drivers/video/pnx4008/pnxrgbfb.c --- a/drivers/video/pnx4008/pnxrgbfb.c 2008-04-07 13:50:27.000000000 +0200 +++ b/drivers/video/pnx4008/pnxrgbfb.c 2008-04-27 12:25:52.000000000 +0200 @@ -100,7 +100,6 @@ static int rgbfb_remove(struct platform_ fb_dealloc_cmap(&info->cmap); framebuffer_release(info); platform_set_drvdata(pdev, NULL); - kfree(info); } pnx4008_free_dum_channel(channel_owned, pdev->id); @@ -168,23 +167,21 @@ static int __devinit rgbfb_probe(struct ret = fb_alloc_cmap(&info->cmap, 256, 0); if (ret < 0) - goto err2; + goto err1; ret = register_framebuffer(info); if (ret < 0) - goto err3; + goto err2; platform_set_drvdata(pdev, info); return 0; -err3: - fb_dealloc_cmap(&info->cmap); err2: - framebuffer_release(info); + fb_dealloc_cmap(&info->cmap); err1: pnx4008_free_dum_channel(channel_owned, pdev->id); err0: - kfree(info); + framebuffer_release(info); err: return ret; }