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 46830C4332F for ; Thu, 5 May 2022 23:48:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1386933AbiEEXwP (ORCPT ); Thu, 5 May 2022 19:52:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353377AbiEEXwN (ORCPT ); Thu, 5 May 2022 19:52:13 -0400 Received: from mail-pf1-x434.google.com (mail-pf1-x434.google.com [IPv6:2607:f8b0:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4B1E606FA for ; Thu, 5 May 2022 16:48:31 -0700 (PDT) Received: by mail-pf1-x434.google.com with SMTP id v11so4895744pff.6 for ; Thu, 05 May 2022 16:48:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=LrHk44z4rhr+J8P+Rl2yRgTdAt0a5Ds6zMRJmsPQsTg=; b=lQJ3Otq3nhLCj2W3ISX1HqEVDcuEnYnmPTO2Pgahhtp8IXa34EJPxmIYEqq3XrYBy2 YWir2n7uRXVITSB/iPQkhoCc8FBMwguoEEmXqXJH+I4z01cOaXd3ou1YYRykm5ixBmnj h6CfFExsGoX5saQ2m8W196HLuEvfUG7vH9ykc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=LrHk44z4rhr+J8P+Rl2yRgTdAt0a5Ds6zMRJmsPQsTg=; b=MsPjE47OV7KtRG0GJSvH5HRx+P5sBDKbkOgHAQBpIsWMychp/tUzdJr0IzIB26a29T 2EF1kl8lRFnzepIevVKMtFYF8rLE3DL9ZC4OajeghxQoeRuBB9KwXswL+b/hsc7PpxcO Rvq1gujPb+oqjIMlE954bpizqmpMxv5GfQMWxFZ1xgDS2sb54Re/MG881TXhPNhy65Ri HefH2X0TZOs7FL/xZnlpBOcJiSle8gER+EufmKGbwiE5DnLUAXfN5ewAGc7Rv00H3I1x P5XgG4lR78XP7/TD0GKorTlqaTsJVtHtUSLVEQjO38l+TLpJG5cmRcfcaiIoXk7MWieH ZVaA== X-Gm-Message-State: AOAM533eOQ5rKqWmerorJ2PMUzBnHecZw/BB4eHP2aWScrXKvwwiNSZ7 tJ3rjv9jRl6/uYX5EeSAMBm9ig== X-Google-Smtp-Source: ABdhPJwZzdK0aRzo196BP9xtL6rZgazn73Kt6i9jFhMZ+TkZuwzvzHY0agoDbi6KbW7R7hmyS02nWQ== X-Received: by 2002:a62:d415:0:b0:50d:baaf:4156 with SMTP id a21-20020a62d415000000b0050dbaaf4156mr804485pfh.28.1651794511222; Thu, 05 May 2022 16:48:31 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id a6-20020a636606000000b003c60b1f0dbasm1903053pgc.35.2022.05.05.16.48.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 May 2022 16:48:30 -0700 (PDT) Date: Thu, 5 May 2022 16:48:29 -0700 From: Kees Cook To: Miguel Ojeda Cc: Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andrew Morton , Sergey Senozhatsky , Kefeng Wang , Helge Deller , Stephen Boyd , Christophe Leroy , Masahiro Yamada , Nick Desaulniers , Changbin Du , Nathan Chancellor , "Gustavo A. R. Silva" , Andi Kleen , Adrian Hunter , linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, linux-perf-users@vger.kernel.org, rust-for-linux@vger.kernel.org, Alex Gaynor , Wedson Almeida Filho , Gary Guo , Boqun Feng Subject: Re: [PATCH v1 3/3] kallsyms: increase maximum kernel symbol length to 512 Message-ID: <202205051647.184C8B2@keescook> References: <20220505191704.22812-1-ojeda@kernel.org> <20220505191704.22812-4-ojeda@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220505191704.22812-4-ojeda@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 05, 2022 at 09:16:45PM +0200, Miguel Ojeda wrote: > Rust symbols can become quite long due to namespacing introduced > by modules, types, traits, generics, etc. For instance, > the following code: > > pub mod my_module { > pub struct MyType; > pub struct MyGenericType(T); > > pub trait MyTrait { > fn my_method() -> u32; > } > > impl MyTrait for MyGenericType { > fn my_method() -> u32 { > 42 > } > } > } > > generates a symbol of length 96 when using the upcoming v0 mangling scheme: > > _RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method > > At the moment, Rust symbols may reach up to 300 in length. > Setting 512 as the maximum seems like a reasonable choice to > keep some headroom. > > Co-developed-by: Alex Gaynor > Signed-off-by: Alex Gaynor > Co-developed-by: Wedson Almeida Filho > Signed-off-by: Wedson Almeida Filho > Co-developed-by: Gary Guo > Signed-off-by: Gary Guo > Co-developed-by: Boqun Feng > Signed-off-by: Boqun Feng > Signed-off-by: Miguel Ojeda I look forward to aiming my demangler at /proc/kallsyms. ;) Reviewed-by: Kees Cook -- Kees Cook