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 03E431D6AA for ; Fri, 24 Oct 2025 10:52:25 +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=1761303147; cv=none; b=gRXF/8/ac4x0rN+54z8Xs5JDN4RCLIfI/FWaqjtkRzxAJw5KUdWz5dVHFOXCuSk/XcPAZ63ZInFXYJ/ikx/H0jtFZRhrEuxNOTG8XP12k/CLdHnJo8E33+pYSdcnqN42sYkZ87Wgbpy5ekfaogJT84fMUfXWvTbxAbJj1pajZ8I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761303147; c=relaxed/simple; bh=oR9fr4/cj1v98n5y9lWOkrmcH2Vx7fCTx7V15NnfFsE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JPCMQWRcIasXLgL7flOQ2eO/LQ0d0cNCAOCk5I77e8PdDCPBt+YiLVK8/sBWV/Hglh+dH93j79twfcBMwkwaSiTrGRmE0jFHCX7bRszCOHO6ck8g/5QT2LJ1OLs/+Woh6+dDXe/zXGMw6gYRw6SbL3RIqnfEx821SIORUs2KYlc= 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=T5m97qC/; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=u5ZhHpHM; 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="T5m97qC/"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="u5ZhHpHM" Date: Fri, 24 Oct 2025 12:52:22 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1761303143; 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=TjAhEWMmIoGnnfhEzLQEZHmdmHxc7Bd3jy4l8L0fvyM=; b=T5m97qC/Hb6qYcst+b+1S6xA/goxk48d0iasq5rIFxkG+43q+TsCy1j+lInhGi7pz0PXDb Tvi2tE8o9vKhADlfr9/A4EhMgKpVRxE9U4sWxcp5smikFftD20mCZ4tNCKaACBBaq33HgA j7k+7NozDVPVQwd/U/TRzKq9d893V9a9MFM2DQdaX8VTEakerBIMvZwsYvb8Z5efwN9fJH ARKi2+l0g+6BLskG5aN+PTe7lbgq5+f/Af813/zEaF+LnX88OOVWMxh/Pwbj1ioPWPeIKj z4pKUZvC+21cmwngplT6gw9glLogUUcUy0nxRvQbYLZXw2LJX7A8Aqq6xlVIuQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1761303143; 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=TjAhEWMmIoGnnfhEzLQEZHmdmHxc7Bd3jy4l8L0fvyM=; b=u5ZhHpHMO2cXf+T4Kt4odPK1y0NvoplRLSsZWX7vajdzSxhkgkiwkn/beo+nsp7edsDAAG S6eYTrfn6mEDZFDA== From: Sebastian Andrzej Siewior To: Oleg Nesterov Cc: Petr Mladek , John Ogness , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] printk_legacy_map: use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP Message-ID: <20251024105222.RZPI5xWT@linutronix.de> References: <20251022154115.GA22400@redhat.com> <20251023103234.GA27415@redhat.com> <20251023142655.FvZkeSa-@linutronix.de> <20251024104055.GE771@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20251024104055.GE771@redhat.com> On 2025-10-24 12:40:56 [+0200], Oleg Nesterov wrote: > On 10/23, Sebastian Andrzej Siewior wrote: > > > > On 2025-10-23 12:32:34 [+0200], Oleg Nesterov wrote: > > > printk_legacy_map is used on !PREEMPT_RT to avoid false positives from > > > CONFIG_PROVE_RAW_LOCK_NESTING about raw_spinlock/spinlock nesting. > > > > Could we please get rid of CONFIG_PROVE_RAW_LOCK_NESTING here? This is > > lockdep internal implementation and has nothing to do with printk or > > anything. > > OK, but let me ensure I didn't miss something (again ;). > > I mentioned CONFIG_PROVE_RAW_LOCK_NESTING in the changelog because if > CONFIG_PROVE_RAW_LOCK_NESTING=n, then LD_WAIT_CONFIG == LD_WAIT_SPIN > and lockdep will not complain if spinlock_t nests inside raw_spinlock_t. > > IOW, without CONFIG_PROVE_RAW_LOCK_NESTING printk_legacy_map is not > really needed. This is correct but CONFIG_PROVE_RAW_LOCK_NESTING is kind of a must and should not be an option. This just verifies what we have in Documentation/locking/locktypes.rst and this is not an option. As I explained it earlier in this (or other) thread I removed it and brought it back because on non-RT architectures spilled warnings and people did not want to apply a larger pile of patches because "it did work" and "I don't use RT" and I have so much time available for arguing. It is not an option architectures which support RT. It is one on architectures which do not support RT so they don't have warning and may debug & fix them if they want to. > Oleg. Sebastian