From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id B3D326B002D for ; Mon, 21 Nov 2011 19:33:53 -0500 (EST) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 88F203EE0B5 for ; Tue, 22 Nov 2011 09:33:49 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 6A00C45DE56 for ; Tue, 22 Nov 2011 09:33:49 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 49C7445DE59 for ; Tue, 22 Nov 2011 09:33:49 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 2434BE08003 for ; Tue, 22 Nov 2011 09:33:49 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.240.81.146]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id E474B1DB804C for ; Tue, 22 Nov 2011 09:33:48 +0900 (JST) Date: Tue, 22 Nov 2011 09:32:38 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] Fix virtual address handling in hugetlb fault Message-Id: <20111122093238.9bdbee39.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20111121142720.a5b62c9c.akpm@linux-foundation.org> References: <20111121194832.a0026d3e.kamezawa.hiroyu@jp.fujitsu.com> <20111121142720.a5b62c9c.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "linux-mm@kvack.org" , "kosaki.motohiro@jp.fujitsu.com" , n-horiguchi@ah.jp.nec.com On Mon, 21 Nov 2011 14:27:20 -0800 Andrew Morton wrote: > On Mon, 21 Nov 2011 19:48:32 +0900 > KAMEZAWA Hiroyuki wrote: > > > >From 7c29389be2890c6b6934a80b4841d07a7014fe26 Mon Sep 17 00:00:00 2001 > > From: KAMEZAWA Hiroyuki > > Date: Mon, 21 Nov 2011 19:45:27 +0900 > > Subject: [PATCH] Fix virtual address handling in hugetlb fault > > > > handle_mm_fault() passes 'faulted' address to hugetlb_fault(). > > Then, the address is not aligned to hugepage boundary. > > > > Most of functions for hugetlb pages are aware of that and > > calculate an alignment by itself. Some functions as copy_user_huge_page(), > > and clear_huge_page() doesn't handle alignment by themselves. > > > > This patch make hugeltb_fault() to calculate the alignment and pass > > aligned addresss (top address of a faulted hugepage) to functions. > > > > Does this actually fix any known user-visible misbehaviour? > I just found this at reading codes. And I know 'vaddr' is ignored in most of per-arch implemantation of clear_user_highpage(). It seems, in some arch, vaddr is used for flushing cache. Now, CONFIG_HUGETLBFS can be set on x86,powerpc,ia64,mips,sh,sparc,tile. (by grep) it seems mips and sh uses vaddr in clear_user_(high)page. > It sounds like the code is masking addresses in a lot of different > places. It would be better to do it once, at the top level. Perhaps > this patch makes some of the existing masking obsolete? > I think so. I'd like to check it and post an additional fix if this patch goes. > > index bb28a5f..af37337 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -2629,6 +2629,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, > > static DEFINE_MUTEX(hugetlb_instantiation_mutex); > > struct hstate *h = hstate_vma(vma); > > > > + address = address & huge_page_mask(h); > > --- a/mm/hugetlb.c~mm-hugetlbc-fix-virtual-address-handling-in-hugetlb-fault-fix > +++ a/mm/hugetlb.c > @@ -2639,7 +2639,7 @@ int hugetlb_fault(struct mm_struct *mm, > static DEFINE_MUTEX(hugetlb_instantiation_mutex); > struct hstate *h = hstate_vma(vma); > > - address = address & huge_page_mask(h); > + address &= huge_page_mask(h); > > ptep = huge_pte_offset(mm, address); > if (ptep) { > > is a bit more readable, IMO. > Sure. Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org