From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f174.google.com (mail-pf0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id BD4BF6B0005 for ; Thu, 11 Feb 2016 16:30:28 -0500 (EST) Received: by mail-pf0-f174.google.com with SMTP id e127so35615660pfe.3 for ; Thu, 11 Feb 2016 13:30:28 -0800 (PST) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id sb2si14836060pac.161.2016.02.11.13.30.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Feb 2016 13:30:28 -0800 (PST) Date: Thu, 11 Feb 2016 13:30:26 -0800 From: Andrew Morton Subject: Re: [Bug 112301] New: [bisected] NULL pointer dereference when starting a kvm based VM Message-Id: <20160211133026.96452d486f8029084c4129b7@linux-foundation.org> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: harn-solo@gmx.de Cc: bugzilla-daemon@bugzilla.kernel.org, linux-mm@kvack.org, ebru.akagunduz@gmail.com, Hugh Dickins (switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface). On Thu, 11 Feb 2016 07:09:04 +0000 bugzilla-daemon@bugzilla.kernel.org wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=112301 > > Bug ID: 112301 > Summary: [bisected] NULL pointer dereference when starting a > kvm based VM > Product: Memory Management > Version: 2.5 > Kernel Version: 4.5-rcX > Hardware: All > OS: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: Other > Assignee: akpm@linux-foundation.org > Reporter: harn-solo@gmx.de > Regression: No > > Created attachment 203451 > --> https://bugzilla.kernel.org/attachment.cgi?id=203451&action=edit > Call Trace of a NULL pointer dereference at gup_pte_range > > Starting a qemu-kvm based VM configured to use hughpages I'm getting the > following NULL pointer dereference, see attached dmesg section. > > The issue was introduced with commit 7d2eba0557c18f7522b98befed98799990dd4fdb > Author: Ebru Akagunduz > Date: Thu Jan 14 15:22:19 2016 -0800 > mm: add tracepoint for scanning pages Thanks for the detailed report. Can you please verify that your tree has 629d9d1cafbd49cb374 ("mm: avoid uninitialized variable in tracepoint")? vfio_pin_pages() doesn't seem to be doing anything crazy. Hugh, Ebru: could you please take a look? -- 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