From owner-svn-src-all@freebsd.org Mon Mar 7 15:52:23 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EFDFAAC2F75; Mon, 7 Mar 2016 15:52:23 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 702B6F67; Mon, 7 Mar 2016 15:52:23 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kostik@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id u27FqHWS074879 (version=TLSv1 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Mon, 7 Mar 2016 17:52:18 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua u27FqHWS074879 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id u27FqH7p074878; Mon, 7 Mar 2016 17:52:17 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 7 Mar 2016 17:52:17 +0200 From: Konstantin Belousov To: Ian Lepore Cc: Dimitry Andric , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r296428 - head/sys/boot/common Message-ID: <20160307155217.GJ67250@kib.kiev.ua> References: <201603061557.u26FvhMi033982@repo.freebsd.org> <56DCD52F.4010709@freebsd.org> <1457365187.13785.174.camel@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1457365187.13785.174.camel@freebsd.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on tom.home X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Mar 2016 15:52:24 -0000 On Mon, Mar 07, 2016 at 08:39:47AM -0700, Ian Lepore wrote: > Is there no way to prevent the panic other than making the unwind data > be present? Why can't the kernel be fixed to cope with the missing > data in some gentler way during a transition period? Perhaps valid-but > -fake data could be generated if necessary? Being unable to get a > stack traceback through a loaded module would be a small price to pay > for trouble-free updgrades. It is practically impossible to recover from partially-loaded object file' module. The loader workaround currently only affects HEAD and since the MFC was done, 10.3 should be safe. We always required lastest stable for the jump to next major branch. What could be done is demoting the panics (there are several, besides the one which was triggered) to a message and refusing to load the affected module. OTOH, if the reaction would be a message and not panic, it definitely go ignored for quite some time.