From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A43CC433F5 for ; Wed, 18 May 2022 10:19:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235054AbiERKTq (ORCPT ); Wed, 18 May 2022 06:19:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235055AbiERKTn (ORCPT ); Wed, 18 May 2022 06:19:43 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9ABBFE7332 for ; Wed, 18 May 2022 03:19:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652869178; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aL2OYkpkQZKWTo+sPUOc1vZdR03lCBjmbztTEGxy9Ao=; b=alLkdEedozksfoeTzHGat9/R5LE2/l0sl2VzHvi5t8q2/LfzLicgDxJdL7493mVzUm177n nBagxF6rD+hfCLswsFdmvQ0fO28Ju7XOxkl2++O+EFZW5n2AqsTvrIkosq+Q/tS1BzROSk 7gXH5BDg+/rWBMX08fguviK3gIjhTo8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-602-IqTzRmmsOtStrwezIiw9Og-1; Wed, 18 May 2022 06:19:34 -0400 X-MC-Unique: IqTzRmmsOtStrwezIiw9Og-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8C84C3C1618C; Wed, 18 May 2022 10:19:33 +0000 (UTC) Received: from localhost (ovpn-13-59.pek2.redhat.com [10.72.13.59]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4848C40C1421; Wed, 18 May 2022 10:19:31 +0000 (UTC) Date: Wed, 18 May 2022 18:19:28 +0800 From: Baoquan He To: Stephen Brennan Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, akpm@linux-foundation.org, Nick Desaulniers , Dave Young , Kees Cook , Jiri Olsa , Stephen Boyd , Bixuan Cui , David Vernet , Vivek Goyal , Sami Tolvanen Subject: Re: [PATCH 0/2] Expose kallsyms data in vmcoreinfo note Message-ID: References: <20220517000508.777145-1-stephen.s.brennan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220517000508.777145-1-stephen.s.brennan@oracle.com> X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/16/22 at 05:05pm, Stephen Brennan wrote: > The kernel can be configured to contain a lot of introspection or > debugging information built-in, such as ORC for unwinding stack traces, > BTF for type information, and of course kallsyms. Debuggers could use > this information to navigate a core dump or live system, but they need > to be able to find it. > > This patch series adds the necessary symbols into vmcoreinfo, which > would allow a debugger to find and interpret the kallsyms table. Using > the kallsyms data, the debugger can then lookup any symbol, allowing it > to find ORC, BTF, or any other useful data. > > This would allow a live kernel, or core dump, to be debugged without > any DWARF debuginfo. This is useful for many cases: the debuginfo may > not have been generated, or you may not want to deploy the large files > everywhere you need them. > > I've demonstrated a proof of concept for this at LSF/MM+BPF during a > lighting talk. Using a work-in-progress branch of the drgn debugger, and > an extended set of BTF generated by a patched version of dwarves, I've > been able to open a core dump without any DWARF info and do basic tasks > such as enumerating slab caches, block devices, tasks, and doing > backtraces. I hope this series can be a first step toward a new > possibility of "DWARFless debugging". Thanks. Seems no reason to reject, even though I haven't tried drgn. And hope it has no security issue, e.g info leakage, at least I don't see it has. So, Acked-by: Baoquan He