From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (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 720DD368D5E for ; Wed, 24 Jun 2026 13:53:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782309184; cv=none; b=MhCSwvKprNjgZPM53HHHAvk9ECkS19R+Q1y412zuq4AsTjAMorJXriSohVsZt9SyyYvwLDGt2jtGmJ8EWMDuUkDJUTppjIcQqc3r60BOzCdP8gJ9IvBxc9rU6qhZFeN/mz4yiNjSTgbDWHQbWgQan1EgMpnF73Dr8pxBXJBXiOc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782309184; c=relaxed/simple; bh=zkgzcPiM97rc0S6TjcXijaCroXS3ki3QLJ2F7L4B3OI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=EPbm376P+Z8KcR9SOe1vevy+/nMPkEoF7qm0GNyW8cfWrkuSWzFo2wFFGC0IbdTdS0Py38vbiViBbttGgZlEkVSKw2MROE7noIBsEfHUiKOoYAWkNS9CzHejByM8MbuJqmKiCbYxU91jb55PP3RdXL7iT9zsqNwZJJJ+mBSqTss= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=CFqzbUvc; arc=none smtp.client-ip=91.218.175.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="CFqzbUvc" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1782309180; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=R/9pZJlHpMdXgadRpz+8VRUR/QVFe1YS13n2B65x7Qc=; b=CFqzbUvcgf6rD+0uLkTBOTlrbupg70NmWia/ySyd0lJb8UY2sRuYyr1Fjd8CtVYJniv09V eSWZ/p01MccP8v1cbSahz/xz2z3YzLEoqTuPSrvJF+vnOh0OC32nQYtc6q525jSRj+sEVf Lh+rdLEPtZLienXKyCyK8ylVRYl7Afs= Date: Wed, 24 Jun 2026 06:52:54 -0700 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH dwarves v7 0/5] pahole: Encode true signatures in kernel BTF Content-Language: en-GB To: Jiri Olsa , Alan Maguire Cc: Arnaldo Carvalho de Melo , dwarves@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , bpf@vger.kernel.org, kernel-team@fb.com References: <20260623040704.2732530-1-yonghong.song@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yonghong Song In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 6/24/26 2:28 AM, Jiri Olsa wrote: > On Tue, Jun 23, 2026 at 05:02:30PM +0100, Alan Maguire wrote: > > SNIP > >>>> hi, >>>> I tried to get the numbers from my setup and noticed that some new >>>> functions were included in BTF compared to the current version >>>> (functions diff attached below) >>>> >>>> like for "arp_process" function the current pahole gives me: >>>> >>>> arp_process : skipping BTF encoding of function due to unexpected register usage for parameter >>>> >>>> but it's included in BTF generated with the new pahole. >>>> >>>> in addition to your explanation above also one of the commit says: >>>> >>>> - a parameter with no location, a constant value, or (for non-clang) no >>>> register found is marked optimized out >>>> >>>> please check below, it seems like 2nd argument of arp_process has no location, >>>> so iiuc it should not be included in BTF, right? >>>> >>>> thanks, >>>> jirka >>>> >>>> >>> thanks for catching this; it looks like we return a bit early before detecting >>> missing locations in the non-true-signature code. If you get a chance, would you >>> mind trying the attached patch to see if it fixes the problem? >>> >>> If the fix works and Yonghong is happy with it we can add it as a followup >>> and land the true signature series to save another round. >> actually sorry that patch leaked true signature partial names for gcc; updated >> patch attached. > hum, I can't apply either of them, but I see that change on top of: > alan-maguire/dwarves-true-sig-v7 > > but on that branch I can still see arp_process function in the btf > > please let me know if I should try some other branch Jiri, Please take a look at v9: https://lore.kernel.org/bpf/20260624052553.3139112-1-yonghong.song@linux.dev/ It has version 7 plus Alan's changes in version 7 comments. I forther added a few changes related to llvm and another patch to resolve some inconsistency. Thanks! Yonghong > > thanks, > jirka