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 377EAC00144 for ; Mon, 1 Aug 2022 13:47:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231910AbiHANrJ (ORCPT ); Mon, 1 Aug 2022 09:47:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230390AbiHANrH (ORCPT ); Mon, 1 Aug 2022 09:47:07 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD04833404 for ; Mon, 1 Aug 2022 06:47:06 -0700 (PDT) Date: Mon, 1 Aug 2022 15:47:03 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1659361624; 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: in-reply-to:in-reply-to:references:references; bh=VBegCjVa+YzCsgk81wGrCFIlyLBGmWu7lUSG3BH6/uQ=; b=Ewn1KI66JzdtCoadPTYqizLiCfOYv4H1Src3G6SiJqBqib1VcwMDRn3bbBj00z6Lqc2E8R 1uyJJRFJqhjXuT+szjYcQA6urCajVwWIoYFlYv2ejMN3yyIZ52jiWZKjqIXulbSInc2GMd 34gYF2hA6k796vet3DSPB+31qkmwBk27ftdsjmI88R2SzarSPmpyfx58+lu0GHi9ZhFHHe GEXV9ET0C165uA9rYmuIGN07KmNB7Pv7P007Au7g7KJei6+YxyKDap+dMTqeAX10GFWYV1 x3SkIxZQvZCx/lFjB438DgGZ7bgCFyt+zlRq3sLyeRVbX1hkEqq6xMvOdsOG2g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1659361624; 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: in-reply-to:in-reply-to:references:references; bh=VBegCjVa+YzCsgk81wGrCFIlyLBGmWu7lUSG3BH6/uQ=; b=axeBgm9iMjeWW5TrcalRl7NmWF9Cfjr5oXBzNZgJZu597V13wWKvNuq2mmovuKc//9DhQ6 UwbmsUFlvAVPNQAQ== From: Sebastian Andrzej Siewior To: "Jason A. Donenfeld" Cc: linux-kernel@vger.kernel.org, Andy Shevchenko , John Ogness , Mike Galbraith , Petr Mladek , Rasmus Villemoes , Sergey Senozhatsky , Steven Rostedt , Theodore Ts'o , Thomas Gleixner Subject: Re: [PATCH v4] lib/vsprintf: defer filling siphash key on RT Message-ID: References: <20220801123945.43081-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022-08-01 15:36:32 [+0200], Jason A. Donenfeld wrote: > Hi Sebastian, Hi Jason, > > Can have the same behaviour regardless of CONFIG_PREEMPT_RT? Here > > lockdep _may_ yell with !RT because it is broken for RT. > > If we agree that we drop the first %p print here, can we do this on > > both (regardless of CONFIG_PREEMPT_RT)? > > "Lockdep may yell" -- but this would be when lockdep is turned on to > catch RT bugs, not to catch non-RT bugs. The actual bug only exists on > RT. This is an RT problem. Stop pretending that this is a real issue > outside of RT. It isn't. This is *only* an RT issue. So why would we > make things worse for an issue that doesn't actually exist on non-RT? You do remember the warning that poped up in random core with CONFIG_PROVE_RAW_LOCK_NESTING enabled? Where I said it does not affect !RT it just points out a RT problem in a !RT config? If you fix this with one code path for RT and another one for !RT then you will have this warning _if_ the caller has a raw_spinlock_t acquired. > I too generally prefer having only one code path and not two. But the > way this patch is written, the worker function just gets reused with a > straight call on the non-RT case, so it doesn't actually require > duplicating code. > Jason Sebastian