From patchwork Sun Mar 24 17:49:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Sperl X-Patchwork-Id: 10867635 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C106C922 for ; Sun, 24 Mar 2019 17:51:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A6FE028870 for ; Sun, 24 Mar 2019 17:51:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 97C832913A; Sun, 24 Mar 2019 17:51:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 50E2328870 for ; Sun, 24 Mar 2019 17:51:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=GfVdNQ1/CtaOLpRd95NnEJDKbka1p2pIGwyhjoHF8BE=; b=Jyv9PDcvMvYu08WllrATnD0sww vJzUVDKVxsCwV4ZR898rXeLdO10JPVv+ufUSjkUcSfNXgrS0sxFprzqT0fCOCLkwUs0qTfDWYCxVo gu2WTmNfa+e1xuCY1v7MxBtvyPk66ZGyjHIEaXQkyoeBXVMadYqBggpazjJDg/ncAO509mm+Th+xa 1QklpRMD2xGgqVF9ew/IrbyK42KW9mHHkIG+Lf3ATQJMxTszZTJaGVj7cZMnODkVJXSoElNFgY0VH xfmCLi8erQbYM+XbPuHy2liB6nqh1Aj408FdKGAr4OkqQFEMFD6H5M/SMvJapkc5SeOkUeRcVXBqa pkhD90uA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h87Gq-0008C1-6P; Sun, 24 Mar 2019 17:50:56 +0000 Received: from 212-186-180-163.static.upcbusiness.at ([212.186.180.163] helo=cgate.sperl.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h87GL-0007UD-Pz; Sun, 24 Mar 2019 17:50:29 +0000 Received: from hc1.intern.sperl.org (account martin@sperl.org [10.10.10.59] verified) by sperl.org (CommuniGate Pro SMTP 6.2.1 _community_) with ESMTPSA id 7759423; Sun, 24 Mar 2019 17:50:10 +0000 From: kernel@martin.sperl.org To: Mark Brown , Eric Anholt , Stefan Wahren , Hubert Denkmair , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH V2 2/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo Date: Sun, 24 Mar 2019 17:49:55 +0000 Message-Id: <20190324175002.28969-3-kernel@martin.sperl.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190324175002.28969-1-kernel@martin.sperl.org> References: <20190324175002.28969-1-kernel@martin.sperl.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190324_105026_326487_062E9787 X-CRM114-Status: UNSURE ( 6.46 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Martin Sperl MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Martin Sperl 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: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e Suggested-by: Hubert Denkmair Signed-off-by: Martin Sperl --- drivers/spi/spi-bcm2835aux.c | 7 ------- 1 file changed, 7 deletions(-) -- 2.11.0 diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 41366d0a16af..0838dbda57c7 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)