From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 453682135A3; Thu, 27 Mar 2025 13:59:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743083946; cv=none; b=lrQI5+JA35WpB1FymCaUwPNpPNdSol3mA3U6L5ardPylK2ZB9JRIMHQxM/6VsQGN2jiLdWPTVKsYlXYhKEBcIGctORpwYOhO/Hs6fR8CcJ26Y0Su2lGueW2iYFXBQFGkSqIz/3L5Mh99k12e21Py7/se6rERqxM9kE036KDg87I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743083946; c=relaxed/simple; bh=78CKgEMvRQkbdzTPJ+Xne53gscygabpMe9qBqj7Tk1s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I1SG4dGKRqC2/jiXhRGeH7jnsivXZD+izEbbeRJX5xIBEj4VJpzuEqWe4xC1zs+wQVN6yLGWQkc+ynBH+WxaOQivdaMatYiikYdJu7BeGvJkHd4Uce9FewpwxG4s6jC/AB+C3BQbKq+v+PnYnDncZ69rhTzPVmW0nP1f1N/gw3k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=gwGAgIht; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="gwGAgIht" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=5CMeCPgUrQopCoTB3t4yW9aHs6rSz31HSjq2nTZBe4E=; b=gwGAgIht+WbwSOrFXJ5rnAekXL b7yVOqD9H3d4p6G4uzmXvJLAzwB2O1Q18SA0yaLLCc3w4fCedHKjQ8/yUfW03JMLOwLo2h7FaJSqP 72HZbRG8wiKAj6PGwI7Rgo+2V2ppuByYZX+Ar5pp47ttjBlPdMjfeX7pdAkM456z03CGhSS5Oit7N KECCmmH4/metUIC8rLnvllxAvm477NLLA/+qfh0ZhIku37UyVUh4sAce/AjB89fOQ1gphrmMNGEvz b+LDhmUgqQfY6Ku4O2GGFwm8E83+jRMmAPaFX7h5IfP+lvap2uqJhikGsOd+eMYzzPjyNgoDD19ck EzYGUMMg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.1 #2 (Red Hat Linux)) id 1txnku-00000005zFK-1r7z; Thu, 27 Mar 2025 13:58:48 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 084A23004AF; Thu, 27 Mar 2025 14:58:48 +0100 (CET) Date: Thu, 27 Mar 2025 14:58:47 +0100 From: Peter Zijlstra To: Arnd Bergmann Cc: Sergio =?iso-8859-1?Q?Gonz=E1lez?= Collado , Brendan Higgins , David Gow , Miguel Ojeda , Alex Gaynor , linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com, Dave Hansen , "H. Peter Anvin" , Josh Poimboeuf , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , David Rheinsberg , rust-for-linux@vger.kernel.org, skhan@linuxfoundation.org, ricardo.marliere@suse.com, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Martin Rodriguez Reboredo , linux-kernel@vger.kernel.org Subject: Re: Symbol too long for allsyms warnings on KSYM_NAME_LEN Message-ID: <20250327135847.GE31358@noisy.programming.kicks-ass.net> References: <66f3f697-530a-4d22-979a-1472c8e8de3a@app.fastmail.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <66f3f697-530a-4d22-979a-1472c8e8de3a@app.fastmail.com> On Thu, Mar 27, 2025 at 09:38:46AM +0100, Arnd Bergmann wrote: > My randconfig builds sometimes (around one in every 700 configs) run > into this warning on x86: > > Symbol __pfx_snnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7n too long for kallsyms (517 >= 512). > Please increase KSYM_NAME_LEN both in kernel and kallsyms.c > > The check that gets triggered was added in commit c104c16073b > ("Kunit to check the longest symbol length"), see > https://lore.kernel.org/all/20241117195923.222145-1-sergio.collado@gmail.com/ > > and the overlong identifier seems to be the result of objtool adding > the six-byte "__pfx_" string to a symbol in elf_create_prefix_symbol() > when CONFIG_FUNCTION_PADDING_CFI is set. > > I think the suggestion to "Please increase KSYM_NAME_LEN both in > kernel and kallsyms.c" is misleading here and should probably be > changed. I don't know if this something that objtool should work > around, or something that needs to be adapted in the test. Probably test needs to be fixed; objtool can't really do anything here, it just take the existing symname and prefixes it.