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 X-Spam-Level: X-Spam-Status: No, score=-7.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70CEAC4363D for ; Wed, 7 Oct 2020 12:09:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35C44206A1 for ; Wed, 7 Oct 2020 12:09:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602072577; bh=svwLuI3ftJyxkOSAbrlX92yzVeoZDHveLEVuxgFyL80=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=TkjmpkL+/7fvE2LqvRU0WffbawkyZU6FkfAyToSl03KaUllEDBro66qb6DTR1Z8+Z LBGbWOkDIYFSOj5qwZBpOc4do9t8FfO/Re7e2drESaBv7QC4ocyu78UrorbVpzgB8F BzPS5eWaxmTn5fciT4R20ciWBwubhp0KmRtW6ShU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728037AbgJGMJg (ORCPT ); Wed, 7 Oct 2020 08:09:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:39870 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728008AbgJGMJg (ORCPT ); Wed, 7 Oct 2020 08:09:36 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 84BCB206A1; Wed, 7 Oct 2020 12:09:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602072575; bh=svwLuI3ftJyxkOSAbrlX92yzVeoZDHveLEVuxgFyL80=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Qd8tOqzGzQU3zyau3RibXuEcAgwdUPLk9YyaPuJha5XoSaotf3WNAoyIEBM68edXD PPd2RvyOJ7OIgXYgoWXw/bOARS9DfEyN4pz+TylwSchAHLkOpqVYbmGjil9ymb4UAo Dfh84VSKfNpNt5icqvP3brRXkkaDUgAkht4BRlm4= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1kQ8GD-000LWr-FR; Wed, 07 Oct 2020 13:09:33 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 07 Oct 2020 13:09:33 +0100 From: Marc Zyngier To: Andy Shevchenko Cc: Linus Walleij , "open list:GPIO SUBSYSTEM" , linux-kernel@vger.kernel.org, Bartosz Golaszewski , kernel-team@android.com Subject: Re: [PATCH] gpio: pca953x: Survive spurious interrupts In-Reply-To: References: <20201005140217.1390851-1-maz@kernel.org> User-Agent: Roundcube Webmail/1.4.8 Message-ID: <0175d3ce84ea0aa938a3ce9b3731762e@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: andy.shevchenko@gmail.com, linus.walleij@linaro.org, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, bgolaszewski@baylibre.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On 2020-10-07 13:02, Andy Shevchenko wrote: > On Wed, Oct 7, 2020 at 12:49 PM Linus Walleij > wrote: >> >> On Mon, Oct 5, 2020 at 4:02 PM Marc Zyngier wrote: >> >> > The pca953x driver never checks the result of irq_find_mapping(), >> > which returns 0 when no mapping is found. When a spurious interrupt >> > is delivered (which can happen under obscure circumstances), the >> > kernel explodes as it still tries to handle the error code as >> > a real interrupt. >> > >> > Handle this particular case and warn on spurious interrupts. >> > >> > Signed-off-by: Marc Zyngier > > Wait, doesn't actually [1] fix the reported issue? Not at all. > Marc, can you confirm this? > > [1]: e43c26e12dd4 ("gpio: pca953x: Fix uninitialized pending variable") Different bug, really. If an interrupt is *really* pending, and no mapping established yet, feeding the result of irq_find_mapping() to handle_nested_irq() will lead to a panic. Recently seen on a Tegra system suffering from even more pathological bugs. M. -- Jazz is not dead. It just smells funny...