From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f182.google.com (mail-wi0-f182.google.com [209.85.212.182]) by kanga.kvack.org (Postfix) with ESMTP id 6C09D6B0255 for ; Tue, 15 Sep 2015 15:01:47 -0400 (EDT) Received: by wicgb1 with SMTP id gb1so42323081wic.1 for ; Tue, 15 Sep 2015 12:01:46 -0700 (PDT) Received: from mail-wi0-f181.google.com (mail-wi0-f181.google.com. [209.85.212.181]) by mx.google.com with ESMTPS id p1si784060wiz.31.2015.09.15.12.01.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 15 Sep 2015 12:01:46 -0700 (PDT) Received: by wiclk2 with SMTP id lk2so40636120wic.1 for ; Tue, 15 Sep 2015 12:01:46 -0700 (PDT) Date: Tue, 15 Sep 2015 22:01:44 +0300 From: "Kirill A. Shutemov" Subject: Re: Multiple potential races on vma->vm_flags Message-ID: <20150915190143.GA18670@node.dhcp.inet.fi> References: <55EC9221.4040603@oracle.com> <20150907114048.GA5016@node.dhcp.inet.fi> <55F0D5B2.2090205@oracle.com> <20150910083605.GB9526@node.dhcp.inet.fi> <20150911103959.GA7976@node.dhcp.inet.fi> <55F8572D.8010409@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55F8572D.8010409@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin Cc: Hugh Dickins , Andrey Konovalov , Oleg Nesterov , Rik van Riel , Andrew Morton , Dmitry Vyukov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka On Tue, Sep 15, 2015 at 01:36:45PM -0400, Sasha Levin wrote: > On 09/11/2015 09:27 PM, Hugh Dickins wrote: > > I'm inclined to echo Vlastimil's comment from earlier in the thread: > > sounds like an overkill, unless we find something more serious than this. > > I've modified my tests to stress the exit path of processes with many vmas, Could you share the test? > and hit the following NULL ptr deref (not sure if it's related to the original issue): > > [1181047.935563] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN > [1181047.937223] Modules linked in: > [1181047.937772] CPU: 4 PID: 21912 Comm: trinity-c341 Not tainted 4.3.0-rc1-next-20150914-sasha-00043-geddd763-dirty #2554 > [1181047.939387] task: ffff8804195c8000 ti: ffff880433f00000 task.ti: ffff880433f00000 > [1181047.940533] RIP: unmap_vmas (mm/memory.c:1337) Is it "struct mm_struct *mm = vma->vm_mm;"? -- Kirill A. Shutemov -- 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