Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753978AbXFVFhx (ORCPT ); Fri, 22 Jun 2007 01:37:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751505AbXFVFhq (ORCPT ); Fri, 22 Jun 2007 01:37:46 -0400 Received: from extu-mxob-1.symantec.com ([216.10.194.28]:57586 "EHLO extu-mxob-1.symantec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751403AbXFVFhp (ORCPT ); Fri, 22 Jun 2007 01:37:45 -0400 Date: Fri, 22 Jun 2007 06:37:03 +0100 (BST) From: Hugh Dickins X-X-Sender: hugh@blonde.wat.veritas.com To: Christoph Lameter cc: Nicolas Ferre , ARM Linux Mailing List , Linux Kernel list , Marc Pignat , Andrew Victor , Pierre Ossman , Andrew Morton , Linus Torvalds , Russell King Subject: Re: Oops in a driver while using SLUB as a SLAB allocator In-Reply-To: Message-ID: References: <467A4532.40301@rfo.atmel.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Brightmail-Verdict: VlJEQwAAAAIAAAABAAAAAAAAAAEAAAAAAAAACmluYm94AGxpbnV4LWtlcm5lbEB2Z2VyLmtlcm5lbC5vcmcAY2xhbWV0ZXJAc2dpLmNvbQBhbmRyZXdAc2FucGVvcGxlLmNvbQBuaWNvbGFzLmZlcnJlQHJmby5hdG1lbC5jb20AbGludXgtYXJtLWtlcm5lbEBsaXN0cy5hcm0ubGludXgub3JnLnVrAGFrcG1AbGludXgtZm91bmRhdGlvbi5vcmcAdG9ydmFsZHNAbGludXgtZm91bmRhdGlvbi5vcmcAbWFyYy5waWduYXRAaGV2cy5jaABkcnpldXNAZHJ6ZXVzLmN4AHJta0Bhcm0ubGludXgub3JnLnVrAA== X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1046 Lines: 23 On Thu, 21 Jun 2007, Christoph Lameter wrote: > On Fri, 22 Jun 2007, Hugh Dickins wrote: > > > However... what gives you confidence that flush_dcache_page is > > never applied to other slab pages? > > Flush dcache page is supposed to run on pages not objects of varying > length. It is suprising that this has not lead to earlier problems. > Objects allocated this way may straddle a page boundary under some > conditions and in that case virt_to_page may not lead to a page that > covers the complete object that is supposed to be flushed. Hopefully the > "size" of the allocated object were whole pages. No, that's the wrong way round. Neither ARM nor PA-RISC expects flush_dcache_page to flush any dcache when given a slab allocation: they just expect it to pass through, not to oops. Hugh - 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/