From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (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 11587195811 for ; Fri, 11 Jul 2025 17:23:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752254597; cv=none; b=RkuxinbJtbobIoTFjRYICDmpCTdwWba3q+PKtTUHTDofSmR/cqUEC0Bzja0rB+ICGci3NqUaqDA2lbhOPzoXKJ5HIfm6Avc2JKPcDe/bAHiiiThmHt5+Jfd8y5MIt9g3ziy3fHWlviFck5F8EaaqRUGZ8Kbd01Dr0IELtYeLuIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752254597; c=relaxed/simple; bh=x5p7vXQmjH/iInSYF3WD9m7I5ifFQOlgT/aSitLQjkk=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=f5Zvkwjn/5/r/BhZi5/EECn8UevDCGL4mKDQFW33+iTQJ3lAqCHPKgVwhUUbGPgR6lWX9sZ6BSsNQIHL0zpk2Rn+NYF7D1ltjoYbARZzDRsyfSrH9V4PQJ5Zd/ZnbMCv0HmJhHRwYAKcFJHJQyL1Ek6DZerDzkVwphBlVTPWdj4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com; spf=pass smtp.mailfrom=HansenPartnership.com; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b=nzcGYx65; arc=none smtp.client-ip=198.37.111.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=HansenPartnership.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="nzcGYx65" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1752254593; bh=x5p7vXQmjH/iInSYF3WD9m7I5ifFQOlgT/aSitLQjkk=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=nzcGYx65tvHGQNAkpakjLFu+rOap8DTMQXrlO+C6g4wK/Lsg9YGhG7blHY7uK0WqB dY5xnFKW79gs3G6L6jU2vwWWiEhwsHRrnAHy1kQpdx9zb2pRjM32VhSoyKY19xWCWP YpgOcX08ZSsPrtOm3K3r/JjWWxB/Smk3ci8qbj74= Received: from [172.19.0.143] (unknown [99.196.129.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lamorak.hansenpartnership.com (Postfix) with ESMTPSA id B678D1C0277; Fri, 11 Jul 2025 13:22:57 -0400 (EDT) Message-ID: <9ca3a6596596e87e7ee06be3414387859aaadafc.camel@HansenPartnership.com> Subject: Re: [RFC PATCH 2/5] unwind: Export unwind_user symbol to GPL modules From: James Bottomley To: Greg KH , Steven Rostedt Cc: Christoph Hellwig , Mathieu Desnoyers , linux-kernel@vger.kernel.org, Josh Poimboeuf , Masami Hiramatsu , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , tech-board-discuss@lists.linuxfoundation.org Date: Fri, 11 Jul 2025 10:22:50 -0700 In-Reply-To: <2025071124-cola-slouching-9dd2@gregkh> References: <20250709212556.32777-1-mathieu.desnoyers@efficios.com> <20250709212556.32777-3-mathieu.desnoyers@efficios.com> <20250711065742.00d6668b@gandalf.local.home> <2025071124-cola-slouching-9dd2@gregkh> Autocrypt: addr=James.Bottomley@HansenPartnership.com; prefer-encrypt=mutual; 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 8mT2Eh9SkH+YVOmaKsajgZgrBxA7fWmGoxXswEVxJIFj3vW7yNc0C5HaUdYa5iGOMs4kg2ht4s7yy7NRQuh7BifWjo6BQ6k4S1H+6axZucxhSV1L6zN9d+lr3Xo/vy1unzA== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2025-07-11 at 13:38 +0200, Greg KH wrote: > On Fri, Jul 11, 2025 at 06:57:42AM -0400, Steven Rostedt wrote: > >=20 > > [ Adding the TAB to this as well ] > >=20 > > On Fri, 11 Jul 2025 00:36:28 -0700 > > Christoph Hellwig wrote: > >=20 > > > On Wed, Jul 09, 2025 at 05:25:49PM -0400, Mathieu Desnoyers > > > wrote: > > > > Allow the unwind_user symbol to be used by GPL modules, for > > > > instance LTTng.=C2=A0=20 > > >=20 > > > I don't see a LTTng submission or any other user in this series. > > > So the usual prohibition against adding unused exports applies > > > here as usual. > >=20 > > I want to bring up this discussion. I understand there's a policy > > not to add EXPORT_SYMBOL_GPL() unless there's a current user of it > > in the kernel proper. My question is, does this policy have to be > > draconian? >=20 > It's not "draconian", it is "we do not add exports for stuff that is > not in our kernel tree."=C2=A0 Simple, direct, and obvious.=C2=A0 We have= no > idea how, or if, external modules do anything with apis that we > export and do not use internally, so we can't change them without > breaking anything, so it's simpler and more obvious to not even > attempt to care about > them. Since the argument is still going on, I've got to say I agree with Greg: it's not draconian it's a simple technical rule which is easily enforceable and gets us out of making political decisions like what's a "good" use of a symbol and what isn't. Once we start making political decisions about kernel symbol exports we open ourselves up to accusations of partisanship and favouritism ... since we have a clear technical criterion, it's just way easier not to descend that slippery slope. Regards, James