From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vc0-f180.google.com (mail-vc0-f180.google.com [209.85.220.180]) by kanga.kvack.org (Postfix) with ESMTP id E87E06B0098 for ; Fri, 6 Jun 2014 14:26:15 -0400 (EDT) Received: by mail-vc0-f180.google.com with SMTP id hq11so3548045vcb.11 for ; Fri, 06 Jun 2014 11:26:15 -0700 (PDT) Received: from mail-ve0-x22e.google.com (mail-ve0-x22e.google.com [2607:f8b0:400c:c01::22e]) by mx.google.com with ESMTPS id x1si7086454vem.40.2014.06.06.11.26.15 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 06 Jun 2014 11:26:15 -0700 (PDT) Received: by mail-ve0-f174.google.com with SMTP id us18so1569910veb.19 for ; Fri, 06 Jun 2014 11:26:14 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140606174317.GA1741@redhat.com> References: <20140606174317.GA1741@redhat.com> Date: Fri, 6 Jun 2014 11:26:14 -0700 Message-ID: Subject: Re: 3.15-rc8 oops in copy_page_rep after page fault. From: Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Dave Jones , Linux Kernel , linux-mm , Linus Torvalds , "Kirill A. Shutemov" , Andrea Arcangeli , David Rientjes On Fri, Jun 6, 2014 at 10:43 AM, Dave Jones wrote: > > RIP: 0010:[] [] copy_page_rep+0x5/0x10 Ok, it's the first iteration of "rep movsq" (%rcx is still 0x200) for copying a page, and the pages are RSI: ffff880052766000 RDI: ffff880014efe000 which both look like reasonable kernel addresses. So I'm assuming it's DEBUG_PAGEALLOC that makes this trigger, and since the error code is 0, and the CR2 value matches RSI, it's the source page that seems to have been freed. And I see absolutely _zero_ reason for wht your 64k mmap_min_addr should make any difference what-so-ever. That's just odd. Anyway, can you try to figure out _which_ copy_user_highpage() it is (by looking at what is around the call-site at "handle_mm_fault+0x1e0". The fact that we have a stale do_huge_pmd_wp_page() on the stack makes me suspect that we have hit that VM_FAULT_FALLBACK case and this is related to splitting. Adding a few more people explicitly to the cc in case anybody sees anything (original email on lkml and linux-mm for context, guys). Linus -- 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