From owner-freebsd-current@FreeBSD.ORG Mon Apr 15 11:15:45 2013 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 6853D441; Mon, 15 Apr 2013 11:15:45 +0000 (UTC) (envelope-from lattera@gmail.com) Received: from mail-vb0-x232.google.com (mail-vb0-x232.google.com [IPv6:2607:f8b0:400c:c02::232]) by mx1.freebsd.org (Postfix) with ESMTP id 0763D994; Mon, 15 Apr 2013 11:15:44 +0000 (UTC) Received: by mail-vb0-f50.google.com with SMTP id w15so3663507vbb.37 for ; Mon, 15 Apr 2013 04:15:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=QDDO3p3C2LJLA3EMAgrUTYFfR63JlEKDYbKmHl31WdM=; b=mE6j1Mb/Lt/Fz5EMMWQBtV3K8IeAm2AvAPBaz/j5hp1MJpgwnfqAoaTLVMRWTae0rz CfM7XFTYHzou4FduroHYoy8APHWHBe1Nb9IwEtQ29ujSZ6MBKYrVfCp2ba3C+Kst2Ehx YLvMM6Dk0YH02+42se1My4dUhz7i+i2CRMRE2uv44K2hQC0mb28IPb4y2Wlqqd1+VztH HX/D4L64DX2YAVvjSj11kJXumyBAEO2K6HjWtIFG8dEOx9v71jOZHIZVZOOWaFHyGq0m 7n+Aci/BkWESBGcUptN4iYNXnPe0bdYV7AzHFflYZdXQWUCzFeGtjaWxLP8x/qPe2g/D ML1w== MIME-Version: 1.0 X-Received: by 10.220.115.135 with SMTP id i7mr15454812vcq.30.1366024544615; Mon, 15 Apr 2013 04:15:44 -0700 (PDT) Received: by 10.59.2.170 with HTTP; Mon, 15 Apr 2013 04:15:44 -0700 (PDT) In-Reply-To: <20130415083517.GB1410@garage.freebsd.pl> References: <20130414044314.GA1115@reks> <20130415083517.GB1410@garage.freebsd.pl> Date: Mon, 15 Apr 2013 07:15:44 -0400 Message-ID: Subject: Re: r248583 Kernel panic: negative refcount 0xfffffe0031b59168 From: Shawn Webb To: Pawel Jakub Dawidek Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: Gleb Kurtsou , FreeBSD-current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 Apr 2013 11:15:45 -0000 On Mon, Apr 15, 2013 at 4:35 AM, Pawel Jakub Dawidek wrote: > > I did receive Shawn's report some time ago, I even installed Chromium to > try to reproduce it, but it didn't crash for me yet. > > If there are some easy, but reliable steps to reproduce it, like "open > this webpage in tab 1, then this webpage in tab 2, then close tab 1" > that would be great. This kernel coredump is not really useful, as we > this is legitimate case of decrementing reference counter. The problem > is that something decremented it earlier when it shouldn't or it wasn't > incremented somewhere. DTrace might be useful tool here if we could > instrument it to log backtrace of all increments and decrements done by > the Chromium processes. Opening and closing tabs seems to be what does it for me. Try opening/closing tabs that have sites open that use Flash (like YouTube). It seems that I can go longer without a kernel panic these days, but it still does happen. I've pretty much switched to using Firefox. I was able to pinpoint the commit, but I wasn't able to pinpoint the actual code that causes the panic. For what it's worth, I'm also running ZFS on root. I'm not sure if that makes any difference. Pawel, can you give me some DTrace scripts to run? I have DTrace enabled on the machine. Thanks, Shawn