From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 25 Oct 2006 08:41:07 +0100 (BST) From: Hugh Dickins Subject: Re: [PATCH 2/3] hugetlb: fix prio_tree unit In-Reply-To: <20061025070805.GA9628@localhost.localdomain> Message-ID: References: <20061025070805.GA9628@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: David Gibson Cc: Andrew Morton , Ken Chen , Bill Irwin , Adam Litke , linux-mm@kvack.org List-ID: On Wed, 25 Oct 2006, David Gibson wrote: > > Hugh, I'd like to add a testcase to the libhugetlbfs testsuite which > will trigger this bug, but from the description above I'm not sure > exactly how to tickle it. Can you give some more details of what > sequence of calls will cause the BUG_ON() to be called. > > I've attached the skeleton test I have now, but I'm not sure if it's > even close to what's really required for this. I'll take a look, or reconstruct my own sequence, later on today and send it just to you. The BUG_ON was not at all what I was expecting, and I spent quite a while working out how it came about (v_offset wrapped, so vm_start + v_offset less than vm_start, so the huge unmap applied to a non-huge vma before it). Though I'm dubious whether it's really worthwhile devising such a test now. Hugh -- 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