From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e34.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m1JIYtRR003923 for ; Tue, 19 Feb 2008 13:34:55 -0500 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m1JIZ4VD189576 for ; Tue, 19 Feb 2008 11:35:04 -0700 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m1JIZ4vX008395 for ; Tue, 19 Feb 2008 11:35:04 -0700 Subject: Re: [PATCH] hugetlb: ensure we do not reference a surplus page after handing it to buddy From: Adam Litke In-Reply-To: <1203445688.0@pinky> References: <1203445688.0@pinky> Content-Type: text/plain Date: Tue, 19 Feb 2008 12:41:51 -0600 Message-Id: <1203446512.11987.36.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andy Whitcroft Cc: Andrew Morton , Nishanth Aravamudan , William Irwin , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Indeed. I'll take credit for this thinko... On Tue, 2008-02-19 at 18:28 +0000, Andy Whitcroft wrote: > When we free a page via free_huge_page and we detect that we are in > surplus the page will be returned to the buddy. After this we no longer > own the page. However at the end free_huge_page we clear out our mapping > pointer from page private. Even where the page is not a surplus we > free the page to the hugepage pool, drop the pool locks and then clear > page private. In either case the page may have been reallocated. BAD. > > Make sure we clear out page private before we free the page. > > Signed-off-by: Andy Whitcroft Acked-by: Adam Litke -- Adam Litke - (agl at us.ibm.com) IBM Linux Technology Center -- 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