From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 276B26B002D for ; Mon, 21 Nov 2011 17:27:23 -0500 (EST) Date: Mon, 21 Nov 2011 14:27:20 -0800 From: Andrew Morton Subject: Re: [PATCH] Fix virtual address handling in hugetlb fault Message-Id: <20111121142720.a5b62c9c.akpm@linux-foundation.org> In-Reply-To: <20111121194832.a0026d3e.kamezawa.hiroyu@jp.fujitsu.com> References: <20111121194832.a0026d3e.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "kosaki.motohiro@jp.fujitsu.com" , n-horiguchi@ah.jp.nec.com 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? 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? > 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. -- 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