From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 B9EC521FF4D for ; Thu, 23 Oct 2025 15:46:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761234373; cv=none; b=UFoRnKx+k8eu9YefCm4uLquQ93wSijtRUj9iBz732Cmc/Xw1wZkcb1E/h2N3ZyUMeHPx9hkrKQebNWBupu8serZi/wCGU+f+D7BNX0VZoNkkkTeP0AGXNWt54xdSLzHEcDtkgRHv3XZ1F0177cibH/9U6ROmT9aNgEbipRdCB6c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761234373; c=relaxed/simple; bh=4RS49+lW1obmZeqEhAFrgEwYXyMDeyk6cpqEJDmXwGw=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=E58F6vQH1Ijv3l2SJEzQctsSVZMddp91gfy329/9sUGFPL1bwBUMvxiYkgehtleTmMqq7y12cFEBb+OjIxRHtr4BmdOvR+/1yKzn+C0SKC2Vq8ilq4xsRaMXGYStlUCNiK60UHRoRP1brmCyFJU7hUwK1qrt5V5nxCtss+YL02I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=DAJnv+2O; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=j7vXJwTr; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="DAJnv+2O"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="j7vXJwTr" From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1761234369; 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=4RS49+lW1obmZeqEhAFrgEwYXyMDeyk6cpqEJDmXwGw=; b=DAJnv+2OGn7s2K1YH2czcdQOkt+1QqhCtKXQZjCLAQZN+IdqRT5SaWEOuYviS/xukQ+e8M Ff7YZbz11MnzS2BOZ+GEfixSyl9a44vrySAAYgiDYzaV/+PRYwldL6uUfDBMXRmBfWuovw qiFEx/NnteD+tf1ui+31/BpdoZfT0z+4yUeJQ+4HYGkU2eOrMa8yQv9+lSTJ+mZM57V7pG 4hBFY+td+6cVT74QcyJePeVkb2vLGHz2d7QlMCpuoyTHcc4TVcyE/XLVOMmk6jmPWU4Pga T2eqOhloV6Lq/P/xjvJuz0JxigJrJOTmj8dPV9d3fw8MHuWX12F7NdTyvTjxXQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1761234369; 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=4RS49+lW1obmZeqEhAFrgEwYXyMDeyk6cpqEJDmXwGw=; b=j7vXJwTrzJhspp+Lq0GLkMAQg5st5yVK1P4sD8QlMQ44lqobOi9LpZd+Bxr0fw3k6mox1I /fbC04IoIJWrFFCA== To: Sebastian Andrzej Siewior Cc: Oleg Nesterov , Petr Mladek , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] printk_legacy_map: use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP In-Reply-To: <20251023151112.goqBFQcM@linutronix.de> References: <20251022154115.GA22400@redhat.com> <20251023103234.GA27415@redhat.com> <20251023142655.FvZkeSa-@linutronix.de> <87wm4lbqt2.fsf@jogness.linutronix.de> <20251023151112.goqBFQcM@linutronix.de> Date: Thu, 23 Oct 2025 17:52:09 +0206 Message-ID: <87tszpbozi.fsf@jogness.linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On 2025-10-23, Sebastian Andrzej Siewior wrote: >> With PREEMPT_RT, legacy console printing is forced into its own >> dedicated kthread. At runtime this is checked via >> force_legacy_kthread(). So with PREEMPT_RT there is no need for special >> lockdep trickery. Once we can get all the consoles switched over to >> nbcon, !PREEMPT_RT will also not need this lockdep trickery. > > This does not matter. My point is that there no need for this ifdefery. > You say: This might get the nesting wrong but it is fine because the > outer lock should be this. This does not hurt if it is also applied on > RT. _BUT_ on RT you don't even trigger this path so this ifdef is not > needed. I am more concerned if we implement a bug and the outer lock is _not_ what it should be and RT _does_ call this path. IMHO avoiding lockdep-forcing when it is not needed is more important than avoiding the trivial PREEMPT_RT ifdefery. But I will not fight it. John