From owner-freebsd-hackers@FreeBSD.ORG Fri Nov 16 02:49:12 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id E3591466; Fri, 16 Nov 2012 02:49:12 +0000 (UTC) (envelope-from neelnatu@gmail.com) Received: from mail-ia0-f182.google.com (mail-ia0-f182.google.com [209.85.210.182]) by mx1.freebsd.org (Postfix) with ESMTP id 97B7C8FC08; Fri, 16 Nov 2012 02:49:12 +0000 (UTC) Received: by mail-ia0-f182.google.com with SMTP id x2so1784653iad.13 for ; Thu, 15 Nov 2012 18:49:11 -0800 (PST) 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; bh=SwepmvNJ98/muRJDjY1vrFbInlz1HiPkvEU/7uybzNY=; b=Gx+tGlsZKA2oHzJqnItlZWhnSWBkZFQVrxNIT4RPTC6t3A2Cmu3K260cAcg7C62C8B LbNrQwsKP0BuXgt+lR5SI4oadVZYGuf7aM4ssBV1qdSS0aEnoHnI33SF3OW4xm0ESJ2p jtBkHirCewxopoCFfR89Hbly9+Mp7PLAhcqCQfJDjeib8SkzLYKCRDBFxMdnSMCjh6G7 zk56bUoi/VENRkTzQTFCK9V28zCeR8aw8rPXfSko7H15OIgjclzmqvr17GCRMofeQ+GW m+mli3pBzm8WvyvVsH7aQgkLkqPDF18aK44CFuaX6GtPFQlOBPsWRJkCvCiHUspQwiyr P7Qg== MIME-Version: 1.0 Received: by 10.50.33.169 with SMTP id s9mr1875283igi.19.1353034151086; Thu, 15 Nov 2012 18:49:11 -0800 (PST) Received: by 10.64.49.44 with HTTP; Thu, 15 Nov 2012 18:49:10 -0800 (PST) In-Reply-To: References: Date: Thu, 15 Nov 2012 18:49:10 -0800 Message-ID: Subject: Re: stop_cpus_hard when multiple CPUs are panicking from an NMI From: Neel Natu To: attilio@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Cc: "freebsd-hackers@freebsd.org" , Ryan Stone 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: Fri, 16 Nov 2012 02:49:13 -0000 Hi, On Thu, Nov 15, 2012 at 3:41 PM, Attilio Rao wrote: > On Thu, Nov 15, 2012 at 10:58 PM, Ryan Stone wrote: >> At work we have some custom watchdog hardware that sends an NMI upon >> expiry. We've modified the kernel to panic when it receives the watchdog >> NMI. I've been trying the "stop_scheduler_on_panic" mode, and I've >> discovered that when my watchdog expires, the system gets completely >> wedged. After some digging, I've discovered is that I have multiple CPUs >> getting the watchdog NMI and trying to panic concurrently. One of the CPUs >> wins, and the rest spin forever in this code: > > Quick question: can you control the way your watchdog sends the NMI? > Like only to BSP rather than broadcast, etc. It can be done but you really want the NMI to be broadcast since the watchdog is firing because some cpu is "hung" and you don't know which one it is. best Neel > This is tied to the very unique situation that you cannot really > deliver the (second) NMI. > > Attilio > > > -- > Peace can only be achieved by understanding - A. Einstein > _______________________________________________ > 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"