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 X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 337AEC43461 for ; Tue, 13 Apr 2021 15:01:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 15FCF613C5 for ; Tue, 13 Apr 2021 15:01:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343960AbhDMPB6 (ORCPT ); Tue, 13 Apr 2021 11:01:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:33660 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239913AbhDMPBv (ORCPT ); Tue, 13 Apr 2021 11:01:51 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1618326090; h=from:from:reply-to: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=2IjKSBCv3C4jbUL7pL2ucxgwpj3Y/YzLvCHEEk6KOlg=; b=N7DoJyQPpVoAV3KyqL1zbeYGRmgfua+LEVTKobcG5aTrVYjyeSu9pqTzJFh5BsXSnyNscN DcQKAxyio4CuDEOktdkmFpiCIQ/WOSAOF7uADON+EZijn15DK+x1B0c1X77jiX53sNdCz6 DHhqwI29bibWf5lONnAU5lY3uYfwTeY= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E0DD4B30E; Tue, 13 Apr 2021 15:01:29 +0000 (UTC) Date: Tue, 13 Apr 2021 17:01:14 +0200 From: Petr Mladek To: Stephen Boyd Cc: Andrew Morton , linux-kernel@vger.kernel.org, Jiri Olsa , Alexei Starovoitov , Jessica Yu , Evan Green , Hsin-Yi Wang , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , linux-doc@vger.kernel.org, Matthew Wilcox Subject: Re: [PATCH v4 05/13] module: Add printk formats to add module build ID to stacktraces Message-ID: References: <20210410015300.3764485-1-swboyd@chromium.org> <20210410015300.3764485-6-swboyd@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210410015300.3764485-6-swboyd@chromium.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 2021-04-09 18:52:52, Stephen Boyd wrote: > Let's make kernel stacktraces easier to identify by including the build > ID[1] of a module if the stacktrace is printing a symbol from a module. > This makes it simpler for developers to locate a kernel module's full > debuginfo for a particular stacktrace. Combined with > scripts/decode_stracktrace.sh, a developer can download the matching > debuginfo from a debuginfod[2] server and find the exact file and line > number for the functions plus offsets in a stacktrace that match the > module. This is especially useful for pstore crash debugging where the > kernel crashes are recorded in something like console-ramoops and the > recovery kernel/modules are different or the debuginfo doesn't exist on > the device due to space concerns (the debuginfo can be too large for > space limited devices). > > diff --git a/include/linux/module.h b/include/linux/module.h > index 59f094fa6f74..4bf869f6c944 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -11,6 +11,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -367,6 +368,9 @@ struct module { > /* Unique handle for this module */ > char name[MODULE_NAME_LEN]; > > + /* Module build ID */ > + unsigned char build_id[BUILD_ID_SIZE_MAX]; Do we want to initialize/store the ID even when CONFIG_STACKTRACE_BUILD_ID is disabled and nobody would use it? Most struct module members are added only when the related feature is enabled. I am not sure how it would complicate the code. It is possible that it is not worth it. Well, I could imagine that the API will always pass the buildid parameter and module_address_lookup() might do something like #ifndef CONFIG_STACKTRACE_BUILD_ID static char empty_build_id[BUILD_ID_SIZE_MAX]; #endif if (modbuildid) { if (IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)) *modbuildid = mod->build_id; else *modbuildid = empty_build_id; IMHO, this is primary a call for Jessica as the module code maintainer. Otherwise, I am fine with this patch. And it works as expected. Best Regards, Petr