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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 52ABFC433EF for ; Sun, 8 Sep 2019 12:44:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A05321BE5 for ; Sun, 8 Sep 2019 12:44:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567946670; bh=0OjlmtzajQP3fonjsDscpmVG6sUf8ItzbOVzKh6nRrA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lveC1JHCOQhqK5J6qPIrzS/Q30lePhwVlTlneHgBPCOjLyYJeGJIkw3rJgwHMWxGt 7w5bQXALd4V3fFqRqMOoehpOvaSleN4orO4+nvbRk0BEs/QzBPgqaKvLPn1Tw3Ju13 VQPDWXHQy0zdjPpfH8LhtzCzGXndNCngSJ/KmsHo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729812AbfIHMo3 (ORCPT ); Sun, 8 Sep 2019 08:44:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:59112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729789AbfIHMoZ (ORCPT ); Sun, 8 Sep 2019 08:44:25 -0400 Received: from localhost (unknown [62.28.240.114]) (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 35B2C218AE; Sun, 8 Sep 2019 12:44:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567946664; bh=0OjlmtzajQP3fonjsDscpmVG6sUf8ItzbOVzKh6nRrA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hf9oqWTqeTU8NtHrAblE8GCeGlqXufOGAPSEJK8OD1+noGlOqOdz9nGBJXyNg0EDH 9AWRiYnY0zu9vOu5iFBoEVadwidJFyBOqCbpUN0gRONf5G+6jBz+vvH31EGvLmq4D5 f6aro5Q1G+K0+uhi/SvdcIFn2l4d/7tQbViz3g9o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hubert Denkmair , Martin Sperl , Stefan Wahren , Mark Brown , Sasha Levin Subject: [PATCH 4.9 20/26] spi: bcm2835aux: remove dangerous uncontrolled read of fifo Date: Sun, 8 Sep 2019 13:41:59 +0100 Message-Id: <20190908121109.989894140@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190908121057.216802689@linuxfoundation.org> References: <20190908121057.216802689@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit c7de8500fd8ecbb544846dd5f11dca578c3777e1 ] This read of the fifo is a potential candidate for a race condition as the spi transfer is not necessarily finished and so can lead to an early read of the fifo that still misses data. So it has been removed. Fixes: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...") Suggested-by: Hubert Denkmair Signed-off-by: Martin Sperl Acked-by: Stefan Wahren Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-bcm2835aux.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 97cb3beb9cc62..4454d9c6a3dd4 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -194,13 +194,6 @@ static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs) BCM2835_AUX_SPI_STAT_TX_FULL))) { bcm2835aux_wr_fifo(bs); } - - /* and check if we have reached "done" */ - while (bs->rx_len && - (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) & - BCM2835_AUX_SPI_STAT_BUSY))) { - bcm2835aux_rd_fifo(bs); - } } static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id) -- 2.20.1