From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f173.google.com (mail-qc0-f173.google.com [209.85.216.173]) by kanga.kvack.org (Postfix) with ESMTP id 5A0686B007B for ; Mon, 22 Dec 2014 13:05:26 -0500 (EST) Received: by mail-qc0-f173.google.com with SMTP id i17so3684731qcy.32 for ; Mon, 22 Dec 2014 10:05:26 -0800 (PST) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id g6si4263593qga.61.2014.12.22.10.05.24 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 22 Dec 2014 10:05:25 -0800 (PST) Message-ID: <54985D59.5010506@oracle.com> Date: Mon, 22 Dec 2014 13:05:13 -0500 From: Sasha Levin MIME-Version: 1.0 Subject: Re: mm: NULL ptr deref in unlink_file_vma References: <549832E2.8060609@oracle.com> <20141222180102.GA8072@node.dhcp.inet.fi> In-Reply-To: <20141222180102.GA8072@node.dhcp.inet.fi> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" , "david S. Miller" Cc: "linux-mm@kvack.org" , LKML , Andrew Morton , Dave Jones , dave@stgolabs.net On 12/22/2014 01:01 PM, Kirill A. Shutemov wrote: > On Mon, Dec 22, 2014 at 10:04:02AM -0500, Sasha Levin wrote: >> > Hi all, >> > >> > While fuzzing with trinity inside a KVM tools guest running the latest -next >> > kernel, I've stumbled on the following spew: >> > >> > [ 432.376425] BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 >> > [ 432.378876] IP: down_write (./arch/x86/include/asm/rwsem.h:105 ./arch/x86/include/asm/rwsem.h:121 kernel/locking/rwsem.c:71) > Looks like vma->vm_file->mapping is NULL. Somebody freed ->vm_file from > under us? > > I suspect Davidlohr's patchset on i_mmap_lock, but I cannot find any code > path which could lead to the crash. I've reported a different issue which that patchset: https://lkml.org/lkml/2014/12/9/741 I guess it could be related? Thanks, Sasha -- 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