From owner-freebsd-hackers@FreeBSD.ORG Wed Jul 10 20:04:18 2013 Return-Path: Delivered-To: hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id F3341872 for ; Wed, 10 Jul 2013 20:04:17 +0000 (UTC) (envelope-from asomers@gmail.com) Received: from mail-qc0-x231.google.com (mail-qc0-x231.google.com [IPv6:2607:f8b0:400d:c01::231]) by mx1.freebsd.org (Postfix) with ESMTP id BA63C18F2 for ; Wed, 10 Jul 2013 20:04:17 +0000 (UTC) Received: by mail-qc0-f177.google.com with SMTP id n1so3831445qcx.8 for ; Wed, 10 Jul 2013 13:04:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=MZWmvWr2a3/X1UuxMv/Lk93L8/fMxRRqcByrt3uBtu8=; b=RtgfcUsZz8OI+xQC4WksxxQ6zo+gfwM0mfeQaC6DpH2l0KPUpI1sUvGh1w6bBLo82P abGzDjGJZ7YjUJqCH+QrBWDiXjVGxxnzAkwC4ZwTnu+7oDJ8jbpvbqkSd2Q0iNmmIkkM Js6dwhleq1K6RU4uHbozqlDlOvQ+yEu3mQtSPKO5DwhRfVdkXqmvp8Wqs3J1j0zFu81B rAeVyqxyljEnDVpDR3lGSsIRaboRX1E4XKnPu59gV/p7CAgwk869goIPfPNf+iPoJoQo niBPYOXQdWXENitvPzDNTE6OZd+Gf21g2l2SKg9XrfHV9+axyLifou3ln7sUw6nYy8/B Ws6Q== MIME-Version: 1.0 X-Received: by 10.224.8.130 with SMTP id h2mr29434930qah.9.1373486657154; Wed, 10 Jul 2013 13:04:17 -0700 (PDT) Received: by 10.49.37.226 with HTTP; Wed, 10 Jul 2013 13:04:17 -0700 (PDT) In-Reply-To: <9890DFF1-892A-4DCA-9E33-B70681154F43@mail.turbofuzz.com> References: <9890DFF1-892A-4DCA-9E33-B70681154F43@mail.turbofuzz.com> Date: Wed, 10 Jul 2013 14:04:17 -0600 Message-ID: Subject: Re: Kernel dumps [was Re: possible changes from Panzura] From: asomers@gmail.com To: Jordan Hubbard Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Mailman-Approved-At: Wed, 10 Jul 2013 21:55:58 +0000 Cc: hackers@freebsd.org, Julian Elischer X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Jul 2013 20:04:18 -0000 On Wed, Jul 10, 2013 at 12:57 PM, Jordan Hubbard w= rote: > > On Jul 10, 2013, at 11:16 AM, Julian Elischer wrote= : > >> My first candidates are: > > Those sound useful. Just out of curiosity, however, since we're on the = topic of kernel dumps: Has anyone even looked into the notion of an emerge= ncy fall-back network stack to enable remote kernel panic (or system hang) = debugging, the way OS X lets you do? I can't tell you the number of times = I've NMI'd a Mac and connected to it remotely in a scenario where everythin= g was totally wedged and just a couple of minutes in kgdb (or now lldb) qui= ckly showed that everything was waiting on a specific lock and the problem = became manifestly clear. > > The feature also lets you scrape a panic'd machine with automation, runni= ng some kgdb scripts against it to glean useful information for later analy= sis vs having to have someone schlep the dump image manually to triage. It= 's going to be damn hard to live without this now, and if someone else isn'= t working on it, that's good to know too! I don't doubt that it would be useful to have an emergency network stack. But have you ever looked into debugging over firewire? We've had success with it. All of our development machines are connected to a single firewire bus. When one panics, we can remotely debug it with both kdb and ddb. It's not ethernet , but it's still much faster than a serial port. https://wiki.freebsd.org/DebugWithDcons > > - Jordan > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org= "