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=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3991BC433ED for ; Thu, 20 May 2021 14:30:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1BE34610A8 for ; Thu, 20 May 2021 14:30:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239378AbhETObx (ORCPT ); Thu, 20 May 2021 10:31:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:47372 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236853AbhETOb3 (ORCPT ); Thu, 20 May 2021 10:31:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EFD4861002; Thu, 20 May 2021 14:30:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621521007; bh=DwkT+nQymoBm5mEDw50KxpS1sTtx5DPSq6uiROs6fx0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=v0kK+vQb6CCfEXNMqvKXTPIWzmEKVvm8T1pZjg4R7x1j0Z2heovIq0Pm5JLpbLpaR Vk5ofpXLNVXNbK7kgOedujHBJKLyV0HFUr6QzUWlVquXpGUUGSQ6jvmN8PRRkvm74b GaeTeak/FyZrcrAmGuAjRmwwzGJmoZDzQTisVuiM= Date: Thu, 20 May 2021 16:30:05 +0200 From: Greg KH To: Zheyu Ma Cc: cernekee@gmail.com, jirislaby@kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] serial: rp2: disable interrupt in rp2_probe(): Message-ID: References: <1620991027-25856-1-git-send-email-zheyuma97@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1620991027-25856-1-git-send-email-zheyuma97@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 14, 2021 at 11:17:07AM +0000, Zheyu Ma wrote: > In 'rp2_probe', the driver registers 'rp2_uart_interrupt' then calls > 'rp2_fw_cb' through 'request_firmware_nowait'. In 'rp2_fw_cb', if the > firmware don't exists, function just return without initializing ports > of 'rp2_card'. But now the interrupt handler function has been registered, > and when an interrupt comes('rp2' may shares an interrupt line with other > devices), 'rp2_uart_interrupt' may access those ports then causing NULL > pointer dereference or other bugs. > > Fix this by disabling interrupt after registering 'rp2_uart_interrupt', > and enable it in 'rp2_uart_startup'. What prevents an interrupt from coming in right after callin rp2_uart_interrupt()? The driver has to be able to handle that. Why is the interrupt being registered before the firmware is loaded? That should be the proper fix as once you register an interrupt, the driver HAS to be able to properly handle it. thanks, greg k-h