From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754749AbYKOUik (ORCPT ); Sat, 15 Nov 2008 15:38:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751622AbYKOUia (ORCPT ); Sat, 15 Nov 2008 15:38:30 -0500 Received: from casper.infradead.org ([85.118.1.10]:53774 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751518AbYKOUia convert rfc822-to-8bit (ORCPT ); Sat, 15 Nov 2008 15:38:30 -0500 Date: Sat, 15 Nov 2008 12:39:16 -0800 From: Arjan van de Ven To: Hugh Dickins Cc: linux-kernel@vger.kernel.org, htejun@gmail.com, akpm@linux-foundation.org, jens.axboe@oracle.com Subject: Re: [PATCH] Fix kunmap() argument in sg_miter_stop Message-ID: <20081115123916.0d83a89e@infradead.org> In-Reply-To: References: <20081115112751.1d38c072@infradead.org> Organization: Intel X-Mailer: Claws Mail 3.6.0 (GTK+ 2.14.4; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 15 Nov 2008 20:15:15 +0000 (GMT) Hugh Dickins wrote: > On Sat, 15 Nov 2008, Arjan van de Ven wrote: > > >From fd5530ac75a919a20bf7951e90a2b12323e9c0a0 Mon Sep 17 00:00:00 > > >2001 > > From: Arjan van de Ven > > Date: Sat, 15 Nov 2008 11:23:58 -0800 > > Subject: [PATCH] Fix kunmap() argument in sg_miter_stop > > > > kunmap() takes as argument the struct page that orginally got > > kmap()'d, however the sg_miter_stop() function passed it the kernel > > virtual address instead, resulting in "kernel BUG at > > arch/x86/mm/highmem_32.c:115!" > > Your patch looks like a good fix to me, but I don't get how its bug > would manifest as highmem_32.c:115 - that's a check in > kunmap_atomic(), whereas you're fixing a bad address to kunmap(). patch with updated description: >>From 979d181d6199f639ba78c5eadf85857f6a9f3f89 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sat, 15 Nov 2008 11:23:58 -0800 Subject: [PATCH] Fix kunmap() argument in sg_miter_stop kunmap() takes as argument the struct page that orginally got kmap()'d, however the sg_miter_stop() function passed it the kernel virtual address instead, resulting in weird stuff. Somehow I ended up fixing this bug by accident while looking for a bug in the same area. Reported-by: kerneloops.org CC: htejun@gmail.com Signed-off-by: Arjan van de Ven --- lib/scatterlist.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 8d2688f..b7b449d 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -395,7 +395,7 @@ void sg_miter_stop(struct sg_mapping_iter *miter) WARN_ON(!irqs_disabled()); kunmap_atomic(miter->addr, KM_BIO_SRC_IRQ); } else - kunmap(miter->addr); + kunmap(miter->page); miter->page = NULL; miter->addr = NULL; -- 1.6.0.3 -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org