From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx112.postini.com [74.125.245.112]) by kanga.kvack.org (Postfix) with SMTP id E96F16B004D for ; Mon, 12 Nov 2012 06:55:17 -0500 (EST) Received: by mail-vb0-f41.google.com with SMTP id v13so7575597vbk.14 for ; Mon, 12 Nov 2012 03:55:16 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <509D0F86.30607@gmail.com> References: <1352155633-8648-1-git-send-email-walken@google.com> <1352155633-8648-4-git-send-email-walken@google.com> <509D0F86.30607@gmail.com> Date: Mon, 12 Nov 2012 03:55:16 -0800 Message-ID: Subject: Re: [PATCH 03/16] mm: check rb_subtree_gap correctness From: Michel Lespinasse Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin Cc: Andrew Morton , Rik van Riel , Hugh Dickins , linux-kernel@vger.kernel.org, Russell King , Ralf Baechle , Paul Mundt , "David S. Miller" , Chris Metcalf , x86@kernel.org, William Irwin , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, Dave Jones On Fri, Nov 9, 2012 at 6:13 AM, Sasha Levin wrote: > While fuzzing with trinity inside a KVM tools (lkvm) guest, using today's -next > kernel, I'm getting these: > > [ 117.007714] free gap 7fba0dd1c000, correct 7fba0dcfb000 > [ 117.019773] map_count 750 rb -1 > [ 117.028362] ------------[ cut here ]------------ > [ 117.029813] kernel BUG at mm/mmap.c:439! > > Note that they are very easy to reproduce. Thanks for the report. I had trouble reproducing this on Friday, but after Hugh came up with an easy test case I think I have it figured out. I sent out a proposed fix as "[PATCH 0/3] fix missing rb_subtree_gap updates on vma insert/erase". Let's follow up the discussion there if necessary. Cheers, -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- 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