From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794537345; b=KT3EBTjcts79C/YRP9Mi0KwB00TuhOp9geNojBpxrmXd6p8KmH2A7VUf8I2mvLMUWtuh 5qKFn08kSzL1nr0vYB8EKkGZ7nmVWGoFplMmK00fEQc0nbVu16qrDS+J7X80mzzjEkNWp S03qKXSnWI4U9pYFvtxkPNw7mO//TsaRcBc6tWfZTHbNbS9UsGXoBPoY760RbvMejDUPw jXQcx/Tdss5pJlA4KSIcgSyBD4JdVDaSBSXHJOGcu69+t6k0wEBBeIftbZ6ukN4om8a39 1rf1Fld9RkJwB0ED8f6pco+FFvHj0MmmmPt9DdWSejaTvTVqZShdkLTZhz0cnbY2Muw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794537345; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=1AxAtbzl4o18Dc8S2gGBClHTTNXWSJfjlQEN5YnJVP8=; b=Db0VN68I6iw3I7AV7fFER+DKByI405Jndval1z57jKb25V9mwSsJGKFOnPmVU540ho7z FaraepMBThYGP8YIaVvy6Hz3mbe+qxETvDvbwL204UivxgHjgy6S1lODFwyOlZWvcrBbV urxq5WoAZLr8rdEEmQAeyOYaWQeTDT1vevwcg/679bw/qiEUpZg8CN/ElLI22GUc75/gY pjJrbjTnDnHoq6D76S0JbS3vErx7XCAJhiaHYgIsVtzN12x2GfDtc0C0ZGB/AirF1tquU kFrDcjSeyecm+MXPbKJlrYdVTVf8LhC3VbFJXwZAHJTme6VybDZJHEv/ah/LiKtL6hQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="XNOj/6KS"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52F52606A31C; Fri, 13 Nov 2026 02:35:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XNOj/6KS Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E7E11F000C4; Fri, 13 Nov 2026 02:35:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794537345; bh=1AxAtbzl4o18Dc8S2gGBClHTTNXWSJfjlQEN5YnJVP8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=XNOj/6KSTfv/2SzV949emJkrw8rux9axLtj3Zfxm/nA34D9iEQTAAnJDKTWdEoQo0 ZyUXBNwMqXX0/gR7BileAWjtPyAj7gUskaJZe4zVxfABW97qVOOF+6dfRz/zCw5a5G aJAtXp3Y2sL29Y/mlKgpO0O9hrzN6sBo4mhtLhVZ3EpJxCyRXQUR2iIpel1ze5KAmr H0tSEROneypuQUXkAt1Mn/SmAM4ryM+222HGqdbEDT+G6MUhnq7KGtlYQy59VO1tR0 OHRmkqcXZrCB+aw7vQM8KpjloNZ31J59+BivSgyJT2ijdwpfQXh/v0AYyJuFdGW2l2 FuJUGeka40kUw== Date: Thu, 12 Nov 2026 18:35:42 -0800 From: Josh Poimboeuf To: Longjun Luo Cc: peterz@infradead.org, mbenes@suse.cz, pmladek@suse.com, joe.lawrence@redhat.com, song@kernel.org, puranjay@kernel.org, nathan@kernel.org, ndesaulniers@google.com, morbo@google.com, justinstitt@google.com, live-patching@vger.kernel.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 00/11] objtool/klp: DWARF-based cross-build symbol correlation Message-ID: References: <20261104133158.3187525-1-luolongjuna@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20261104133158.3187525-1-luolongjuna@gmail.com> On Wed, Nov 04, 2026 at 09:31:46PM +0800, Longjun Luo wrote: > Responses to v1 Review (Guide) > ------------------------------ > > Thanks to Josh for reviewing v1. v2 responds as follows: > > 1. `CONFIG_DEBUG_INFO` and split/reduced DWARF: as suggested, `klp-build` > now requires `CONFIG_DEBUG_INFO` and uses Kbuild's debug flags > (Patch 6). Reduced and split DWARF are supported (Patch 5). See > "Compatibility Limits and Build Requirements". > > 2. Repeated macro statics and the one-line test: building on the > referencing-function idea, unchanged-function references resolve > repeated statics (Patch 9). The tree-wide test reduces v1's > `no correlation` warnings from 682/764 to zero (GCC/Clang). See > "Evaluation and Performance Overhead". > > 3. Upgrading `no correlation` to an error and explicit annotations: > following this direction, v2 rejects ambiguous data references and > allows verified new data (Patch 10). See Case D for the > state-inheritance boundary, its kernel-wide impact, and proposed > annotations. > > 4. Referencing functions, ThinLTO naming flags, and Full LTO: in ELF, the > referencing function only approximates the defining scope, and > `STT_FILE` and `.llvm.` suffixes only approximate the defining > TU. Definition identity distinguishes inlined helpers' state and > survives LTO renaming and `STT_FILE` merging; see Cases A-B. > > 5. Toolchain reliability and performance: v2 cross-checks DWARF against > ELF and measures checksum/diff costs, including a separate memory > prototype. See "Design Overview", "Evaluation and Performance > Overhead", and "Open Questions and Next Steps". Going forward, please reply directly to the review comments (including sashiko reviews), as threaded emails are much easier to follow/discuss than a summary like the above. -- Josh