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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D05D7C33C9E for ; Tue, 7 Jan 2020 21:12:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B9822077B for ; Tue, 7 Jan 2020 21:12:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578431573; bh=1GQWZNbTZ5SCFaCMF4eC+xm0QO816lskqthPyras80Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pziwJMwi9plMxfn1b6c4Y3lUjYnUche/Kx7QRhRFde/35SBEnqyDXSMo3T1AUyWfy bzRf2RAv9I9yIvvAgZujUlBJ/dXjjoJ+cjokNU8wt/X6U4PcxJakpXwootXPCUaCGS STVWpLSF8Dhl8tx6mcMMdUEUX9HvHk+M6glA2RgI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730041AbgAGVLA (ORCPT ); Tue, 7 Jan 2020 16:11:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:38446 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730037AbgAGVK7 (ORCPT ); Tue, 7 Jan 2020 16:10:59 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 6F49F20880; Tue, 7 Jan 2020 21:10:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578431458; bh=1GQWZNbTZ5SCFaCMF4eC+xm0QO816lskqthPyras80Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ny6z4YMRAEkehJEh4lMRPZ3oEo8oCtwnWyK9jlsRhqFHlzrkU2lqBbrtVo70Gi6vl bCZi/UxWgn35bVd46q7tjnJyJ96VtnLJM1+J/ZQUdFQOLKPM+jGu+cCjWbCTas/UwN NpM1LNl3uupE5Q0TxNHskM4bjbgUXpZ0paB2R/Oo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hans Verkuil , Mauro Carvalho Chehab Subject: [PATCH 4.14 28/74] media: cec: avoid decrementing transmit_queue_sz if it is 0 Date: Tue, 7 Jan 2020 21:54:53 +0100 Message-Id: <20200107205157.979093358@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200107205135.369001641@linuxfoundation.org> References: <20200107205135.369001641@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Hans Verkuil commit 95c29d46ab2a517e4c26d0a07300edca6768db17 upstream. WARN if transmit_queue_sz is 0 but do not decrement it. The CEC adapter will become unresponsive if it goes below 0 since then it thinks there are 4 billion messages in the queue. Obviously this should not happen, but a driver bug could cause this. Signed-off-by: Hans Verkuil Cc: # for v4.12 and up Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/cec/cec-adap.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/drivers/media/cec/cec-adap.c +++ b/drivers/media/cec/cec-adap.c @@ -330,7 +330,8 @@ static void cec_data_cancel(struct cec_d } else { list_del_init(&data->list); if (!(data->msg.tx_status & CEC_TX_STATUS_OK)) - data->adap->transmit_queue_sz--; + if (!WARN_ON(!data->adap->transmit_queue_sz)) + data->adap->transmit_queue_sz--; } /* Mark it as an error */ @@ -377,6 +378,14 @@ static void cec_flush(struct cec_adapter * need to do anything special in that case. */ } + /* + * If something went wrong and this counter isn't what it should + * be, then this will reset it back to 0. Warn if it is not 0, + * since it indicates a bug, either in this framework or in a + * CEC driver. + */ + if (WARN_ON(adap->transmit_queue_sz)) + adap->transmit_queue_sz = 0; } /* @@ -465,7 +474,8 @@ int cec_thread_func(void *_adap) data = list_first_entry(&adap->transmit_queue, struct cec_data, list); list_del_init(&data->list); - adap->transmit_queue_sz--; + if (!WARN_ON(!data->adap->transmit_queue_sz)) + adap->transmit_queue_sz--; /* Make this the current transmitting message */ adap->transmitting = data;