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 B434A763F2 for ; Tue, 20 Feb 2024 16:12:57 +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=1708445579; cv=none; b=aShzKcdRkWpdS9Xk7wJJrzq4lJI6K44uMn1PoE2t/HAejXqcLdwB3+mvGKCvc56YurGC2nORoVoC8h2cXDTRD0rVoSC0TShfjySYZO+K2PjX+lSYVnxuy2qTYpYbfTq7rTJQlbvQd3DA1OBkI85RCqv5KCMuAPJweJyAAGLegTA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708445579; c=relaxed/simple; bh=5tAhIw/LCPQZkqfKPCUp+TgjCjXAEnSGyozQ+zzqwmo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=apbCYQbox3arLEN6pBrmHE6HgsUFc7qEB4mKdQsYXTWnTU1fVqtstLjNbLuLbD9kiTJWDAZLWLp1/GLh6BYno5S84oAnLF38TPXydH1bxTHTo892APjPZROFe8AKWCmXCGvjUdtSmKQW9u5gS2HxKhpyuJQQt/Cj0sf9pIXGoFQ= 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=vhY+zEYo; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Dt3XistD; 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="vhY+zEYo"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Dt3XistD" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1708445575; 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=3ZrY1gZPRUvTnU9/cDlk7x1h0DpwHxopqdoV/0GbhPM=; b=vhY+zEYoC7D9zwqbcnW1119riOcQ+OFEtBVbgAQVG69dJRwRab6ob5mgV+X1aVUvP4t56c cq/TLWNqUmUQcBmKe7eAFZFZ57Jy1QcO4h5eVzfNPN4pprnAbKyyWlwTPqt59igDkB6oTw qxdEgXBQ21aOx95WFj8iPIIp5bJ4YZXC5tYHbrAITXb0uH7+KKEJeqTViUce4zmsnBKfhO SYL+vcWdMA8U3XaR4LL1s2gL9ew6I8/FHvULPPF7tWb9OktJshJglCsl97olL2+NYcwm7T 4jHS6kbCeFo0KuIRYV3lFSoY82jQU2Z61xDJ9Y2TQgQhTmyhlbUAA4w8rDyhoQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1708445575; 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=3ZrY1gZPRUvTnU9/cDlk7x1h0DpwHxopqdoV/0GbhPM=; b=Dt3XistDyurCcEeAaa7TewWu6cHD3oicJDNl30atSYP5EjgqdkCCKSXMvJ15qVqRszkeP2 AHsa+z7/BynoIqDA== To: James Morse , David Hildenbrand , x86@kernel.org, linux-kernel@vger.kernel.org Cc: Fenghua Yu , Reinette Chatre , Ingo Molnar , Borislav Petkov , H Peter Anvin , Babu Moger , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com Subject: Re: [PATCH v9 02/24] x86/resctrl: kfree() rmid_ptrs from resctrl_exit() In-Reply-To: <49f42c63-63b9-4cf9-96ad-901b3fc1d50e@arm.com> References: <20240213184438.16675-1-james.morse@arm.com> <20240213184438.16675-3-james.morse@arm.com> <52f81c45-efa7-42c7-86f4-fc1084b1d57a@redhat.com> <59ebda21-6164-4dff-9ba8-956d5a715048@arm.com> <87v86jgmhp.ffs@tglx> <49f42c63-63b9-4cf9-96ad-901b3fc1d50e@arm.com> Date: Tue, 20 Feb 2024 17:12:55 +0100 Message-ID: <87sf1nglmg.ffs@tglx> 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 Tue, Feb 20 2024 at 16:01, James Morse wrote: > On 20/02/2024 15:54, Thomas Gleixner wrote: >>> With MPAM this code can be invoked from an error IRQ signalled by the hardware, so it >>> could happen anytime. >> >> Which does not work because you can't acquire a mutex from hard >> interrupt context. > > Indeed - which is why that happens via schedule_work() [0] > > My point was that its non-obvious where/when this will happen, so taking the lock and > forgetting about it is the simplest thing to do. Makes sense. Thanks, tglx