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 17729139D07; Tue, 26 Nov 2024 11:20:09 +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=1732620012; cv=none; b=JnNq8ErSCT2K87MNLalbDeYdoqCZPme2LJcCs4uXBrOkDRDtsrewr5B43lz0oAOY1ztTZcWhkXtji/R5jc+Yol5T3xX3UO4/rY0R1ESuTu03pCPFcYjfYCBzaZwQdX4DqHMokoSPM1x1cVABcSCWITYY64Smq4xzcMv11kc/CTo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732620012; c=relaxed/simple; bh=ud+eH7yG+oOTmRuS7cdQfVegR1yQ0UWl53am1ZPomwY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BLvWQjn4kCViy/LMNHlFQn1+ovTkVHHJPanA07sROX3V0uDamwfy88MqL8IPmEJUmOqmMgl3k7xUqPBrdajicoPu2t+5eH4ijPexZ4xLQ+TgYP/BMZCoQxeuv00zs1TgwPWs/OyppUld8kEgTiLG5VPyZe64DkI0yrXHlR8TC6U= 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=rdjzgIB1; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=NtG0SDPr; 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="rdjzgIB1"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="NtG0SDPr" Date: Tue, 26 Nov 2024 12:20:00 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1732620002; 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=ud+eH7yG+oOTmRuS7cdQfVegR1yQ0UWl53am1ZPomwY=; b=rdjzgIB1gdAAPeUW9PwasFAAz2Sn9T+MWkjh1d4XKOQ7AhmUfJOzB9Y1/oipRQKmGACI3z qSAaBOI26NdsPW3ZV/AsBOgq17V4d2j3fDgL2rR75e0heIrYNrEFDDJqdOoakUFa9lQ8qR AqjRBdxZB+zCDUZC1BGZ8Pz+ciLTeVScosCO9qCRuymps4CosDwTB9fvlYb/PK7C7gwXZ0 74pDhn+I4MLJuMST1WQoFhf/ygOT+fM2JHLcEVks+n/lkGC0L7XEmo0mVsXipGLz0SjAEe KGB3dlA+gu8eEY2P2IGj8vf7wW5GkzSoSUixaom3XAyW4S85kGCHefeU/ptHcg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1732620002; 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=ud+eH7yG+oOTmRuS7cdQfVegR1yQ0UWl53am1ZPomwY=; b=NtG0SDPrjEZ7HbAezRxXGee3gWzrdq1YN830e8xKAxI77Np1C6LEcxQ6P84QKhJQ9ew/AN YsDoK98yQUImMxAw== From: Sebastian Andrzej Siewior To: Waiman Long Cc: Guenter Roeck , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, Boqun Feng , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Will Deacon , "David S. Miller" , Andreas Larsson Subject: Re: [PATCH] sparc/pci: Make pci_poke_lock a raw_spinlock_t. Message-ID: <20241126112000.UkTwR0Iv@linutronix.de> References: <20241125085314.1iSDFulg@linutronix.de> <20241125174336.8nEhFXIw@linutronix.de> <20241125181231.XpOsxxHx@linutronix.de> <72991b83-173e-492e-a4aa-5049304c1bd0@roeck-us.net> <5d269249-afd1-44f5-8faf-9ac11d9a3beb@redhat.com> <2a940822-b4d4-43ea-b4f7-4294043b76ea@roeck-us.net> <88f47cea-baba-4673-9bd7-7b7c3f421008@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 Content-Transfer-Encoding: quoted-printable In-Reply-To: <88f47cea-baba-4673-9bd7-7b7c3f421008@redhat.com> On 2024-11-25 15:54:48 [-0500], Waiman Long wrote: > > FWIW, the description of commit 560af5dc839 is misleading. It says > > "Enable > > PROVE_RAW_LOCK_NESTING _by default_" (emphasis mine). That is not what > > the > > commit does. It force-enables PROVE_RAW_LOCK_NESTING if PROVE_LOCKING is > > enabled. It is all or nothing. > >=20 > I think we can relax it by >=20 > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 5d9eca035d47..bfdbd3fa2d29 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1399,7 +1399,7 @@ config PROVE_LOCKING > =C2=A0config PROVE_RAW_LOCK_NESTING > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 bool > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 depends on PROVE_LOCKING > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 default y > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 default y if ARCH_SUPPORTS_RT > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 help > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Enable the raw_spinlock = vs. spinlock nesting checks which ensure > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 that the lock nesting ru= les for PREEMPT_RT enabled kernels are >=20 > Sebastian, what do you think? All the changes Guenter proposed make sense and were limited to sparc. So we could apply that. Limiting the option to the RT architectures would silence the warnings. If there is no interest in getting RT on sparc there is probably no interest in getting the lock ordering straight. I remember PeterZ did not like the option in the beginning but there was no way around it especially since printk triggered it on boot. I'm fine with both solutions (fixing sparc or limiting PROVE_RAW_LOCK_NESTING). I leave the final judgment to the locking people. > Cheers, > Longman Sebastian