Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751327Ab1FBOW6 (ORCPT ); Thu, 2 Jun 2011 10:22:58 -0400 Received: from mail-ew0-f46.google.com ([209.85.215.46]:45059 "EHLO mail-ew0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750872Ab1FBOW5 (ORCPT ); Thu, 2 Jun 2011 10:22:57 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=FzUUWcOkVbdUOCaB3ogxEh3UoOhnFVEzkXBZsGkjfQWzlo9C17/GTtFZHiDumvoYQq 0dKMYGjRU5ZZKZWhn2zW1lGG6tdV0uLD2MjZBVkqq1IqZfvjeRyHJXY7MEnaDO23yEHx 8VOelG0ETboqYCIYElXsBWjC/cv9cKiQp1LIo= Date: Thu, 2 Jun 2011 17:22:42 +0300 From: Maxin B John To: eike-kernel@sf-tec.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, dima@android.com, willy@linux.intel.com, segooon@gmail.com, tj@kernel.org, jkosina@suse.cz, tglx@linutronix.de Subject: Re: [PATCH] mm: dmapool: fix possible use after free in dmam_pool_destroy() Message-ID: <20110602142242.GA4115@maxin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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: 2122 Lines: 58 On Thu, Jun 2, 2011 at 12:47 PM, Rolf Eike Beer wrote: > Maxin B John wrote: >> "dma_pool_destroy(pool)" calls "kfree(pool)". The freed pointer >> "pool" is again passed as an argument to the function "devres_destroy()". >> This patch fixes the possible use after free. > > The pool itself is not used there, only the address where the pool > has been.This will only lead to any trouble if something else is allocated to > the same place and inserted into the devres list of the same device between > the dma_pool_destroy() and devres_destroy(). Thank you very much for explaining it in detail. > But I agree that this is bad style. But if you are going to change > this please also have a look at devm_iounmap() in lib/devres.c. Maybe also the > devm_*irq* functions need the same changes. As per your suggestion, I have made similar modifications for lib/devres.c and kernel/irq/devres.c CCed the maintainers of the respective files. Signed-off-by: Maxin B. John --- diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c index 1ef4ffc..bd8e788 100644 --- a/kernel/irq/devres.c +++ b/kernel/irq/devres.c @@ -87,8 +87,8 @@ void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id) { struct irq_devres match_data = { irq, dev_id }; - free_irq(irq, dev_id); WARN_ON(devres_destroy(dev, devm_irq_release, devm_irq_match, &match_data)); + free_irq(irq, dev_id); } EXPORT_SYMBOL(devm_free_irq); diff --git a/lib/devres.c b/lib/devres.c index 6efddf5..7c0e953 100644 --- a/lib/devres.c +++ b/lib/devres.c @@ -79,9 +79,9 @@ EXPORT_SYMBOL(devm_ioremap_nocache); */ void devm_iounmap(struct device *dev, void __iomem *addr) { - iounmap(addr); WARN_ON(devres_destroy(dev, devm_ioremap_release, devm_ioremap_match, (void *)addr)); + iounmap(addr); } EXPORT_SYMBOL(devm_iounmap); -- 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/