From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e6.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id mB2JOFgA008997 for ; Tue, 2 Dec 2008 14:24:15 -0500 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id mB2JOlGe172076 for ; Tue, 2 Dec 2008 14:24:47 -0500 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id mB2JOkTc021342 for ; Tue, 2 Dec 2008 14:24:46 -0500 Subject: Re: [Bug 12134] New: can't shmat() 1GB hugepage segment from second process more than one time From: Adam Litke In-Reply-To: <20081201181459.49d8fcca.akpm@linux-foundation.org> References: <20081201181459.49d8fcca.akpm@linux-foundation.org> Content-Type: text/plain Date: Tue, 02 Dec 2008 13:24:40 -0600 Message-Id: <1228245880.13482.19.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-mm@kvack.org, bugme-daemon@bugzilla.kernel.org, starlight@binnacle.cx, Andy Whitcroft , David Gibson List-ID: On Mon, 2008-12-01 at 18:14 -0800, Andrew Morton wrote: > > can't shmat() 1GB hugepage segment from second process more than one time > > > > Steps to reproduce: starlight@binnacle.cx: I need more information to reproduce this bug. Please read on. I've tried these steps and haven't been able to reproduce. Are these reproduction steps actually a description of what a more complex program is doing, or have you reproduced this with simple C programs that implement nothing more than the instructions provided in this bug? It would make it easier to diagnose this if you could provide a simple C program that causes the bad behavior. > > > > create 1GB or more hugepage shmget/shmat segment > > attached at explicit virtual address 0x4_00000000 You must mean either 0x400000000 or 0x4000000000; please clarify. (I tried both addresses and was unable to reproduce. Are you touching any of the pages in the shared memory segment with this process? What flags are you passing to shmget and shmat? Could you provide an strace for each program run? > > run another program that attaches segment Does this second program do anything besides attaching the segment (ie. faulting any of the huge pages)? > > run it again, fails > > > > eventually get attached 'dmesg' output > > > > works fine under RHEL 4.6 > > > > -- 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