From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f71.google.com (mail-oi0-f71.google.com [209.85.218.71]) by kanga.kvack.org (Postfix) with ESMTP id 8BBE06B0038 for ; Thu, 13 Oct 2016 00:04:17 -0400 (EDT) Received: by mail-oi0-f71.google.com with SMTP id d132so139812346oib.3 for ; Wed, 12 Oct 2016 21:04:17 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [119.145.14.65]) by mx.google.com with ESMTPS id c10si4446774oib.63.2016.10.12.21.04.13 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 12 Oct 2016 21:04:16 -0700 (PDT) Message-ID: <57FF061D.2030708@huawei.com> Date: Thu, 13 Oct 2016 11:57:17 +0800 From: zhong jiang MIME-Version: 1.0 Subject: Re: [PATCH] z3fold: fix the potential encode bug in encod_handle References: <1476329585-15428-1-git-send-email-zhongjiang@huawei.com> In-Reply-To: <1476329585-15428-1-git-send-email-zhongjiang@huawei.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: vitalywool@gmail.com, david@fromorbit.com, sjenning@redhat.com, ddstreet@ieee.org, akpm@linux-foundation.org, mhocko@kernel.org, vbabka@suse.cz Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org On 2016/10/13 11:33, zhongjiang wrote: > From: zhong jiang > > At present, zhdr->first_num plus bud can exceed the BUDDY_MASK > in encode_handle, it will lead to the the caller handle_to_buddy > return the error value. > > The patch fix the issue by changing the BUDDY_MASK to PAGE_MASK, > it will be consistent with handle_to_z3fold_header. At the same time, > The code will much comprehensible to change the BUDDY_MASK to > BUDDIES_MAX in handle_to_buddy. > > Signed-off-by: zhong jiang > --- > mm/z3fold.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/z3fold.c b/mm/z3fold.c > index 8f9e89c..5884b9e 100644 > --- a/mm/z3fold.c > +++ b/mm/z3fold.c > @@ -169,7 +169,7 @@ static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) > > handle = (unsigned long)zhdr; > if (bud != HEADLESS) > - handle += (bud + zhdr->first_num) & BUDDY_MASK; > + handle += (bud + zhdr->first_num) & PAGE_MASK; > return handle; > } > > @@ -183,7 +183,7 @@ static struct z3fold_header *handle_to_z3fold_header(unsigned long handle) > static enum buddy handle_to_buddy(unsigned long handle) > { > struct z3fold_header *zhdr = handle_to_z3fold_header(handle); > - return (handle - zhdr->first_num) & BUDDY_MASK; > + return (handle - zhdr->first_num) & BUDDIES_MAX; > } > > /* oh, a obvious problem, please ignore it. I will resent the patch in v2. Thanks -- 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/ . Don't email: email@kvack.org