From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f70.google.com (mail-oi0-f70.google.com [209.85.218.70]) by kanga.kvack.org (Postfix) with ESMTP id 01B4C6B0038 for ; Wed, 12 Oct 2016 23:41:34 -0400 (EDT) Received: by mail-oi0-f70.google.com with SMTP id e200so140212754oig.4 for ; Wed, 12 Oct 2016 20:41:33 -0700 (PDT) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com. [58.251.152.64]) by mx.google.com with ESMTPS id 38si4132423otn.283.2016.10.12.20.41.32 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 12 Oct 2016 20:41:33 -0700 (PDT) From: zhongjiang Subject: [PATCH] z3fold: fix the potential encode bug in encod_handle Date: Thu, 13 Oct 2016 11:33:05 +0800 Message-ID: <1476329585-15428-1-git-send-email-zhongjiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain 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 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; } /* -- 1.8.3.1 -- 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