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 169C8ECAAD3 for ; Thu, 8 Sep 2022 00:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229750AbiIHAg3 (ORCPT ); Wed, 7 Sep 2022 20:36:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229513AbiIHAgR (ORCPT ); Wed, 7 Sep 2022 20:36:17 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3F757653; Wed, 7 Sep 2022 17:36:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=nSJLgRjMMl1YkRTkbAlqniyD6fRuPD0gktBDc/jlsrE=; b=TCjCWGiEFMk23m6+LxhdrFDhkv Q+SO4QJj4H79/wc8YSJk3Kky+PrV8n22Pc0jHOAwFq+PZ9FpesfvUS25fYYpHSpSvHwoJ4iEtSu36 Zo7Vzl7AISwqnlGL78+CBGlIE8Nt6+n14KhGs35CQGPClpSZ/iLnUKwyT8JCaYcNGztVoOFGzA+GY mNmB99nCqS4gwKCH8qM3wX4S+7WBC00m6usmaDVB8U0hyIb3NBFXonuflPU70iAbPS4cwWwXKCuSR H/KUCyAX1aDS66TtUiLpOMZHoHSNUkgxN4TVqINPMc+2GF2JoQu4j3TDjrs8Q3Hea5OVMdAwb2N9+ lhDL1U5Q==; Received: from [177.215.76.177] (helo=[192.168.1.60]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1oW5WZ-00D2UE-5F; Thu, 08 Sep 2022 02:36:07 +0200 Message-ID: <887931a4-c1df-8b4b-6594-864b96e50217@igalia.com> Date: Wed, 7 Sep 2022 21:35:49 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Subject: Re: [PATCH V3] firmware: google: Test spinlock on panic path to avoid lockups Content-Language: en-US To: Evan Green , Andrew Morton , Greg KH Cc: Petr Mladek , Arnd Bergmann , linux-efi@vger.kernel.org, LKML , kernel@gpiccoli.net, Ard Biesheuvel , David Gow , Julius Werner References: <20220819155059.451674-1-gpiccoli@igalia.com> <6bc5dbc3-2cdd-5cb8-1632-11de2008a85a@igalia.com> <85683284-db85-7e3a-57bd-750e1c204e3e@igalia.com> <794efe45-2fef-0d3f-b6d0-f2f451be850c@igalia.com> <20220901151320.3cff1767f88cfb33f394e9cb@linux-foundation.org> From: "Guilherme G. Piccoli" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/09/2022 14:09, Evan Green wrote: > [...] > > I basically came to the same conclusion as Andrew. It seems like this > patch does fix a problem, which is a panic coming in on another CPU > and NMIing on top of a CPU doing a normal operation holding this lock. > The problem seems pretty theoretical, but I suppose I don't have > numbers one way or another since any attempt to gather numbers would > be reliant on this very mechanism. My Reviewed-by tag is already on > there. > -Evan Thanks for the feedback Evan and Andrew. So if Greg (or anybody else) doesn't oppose, I'll send a V4 with the commit message/comment suggestions. Cheers, Guilherme