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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC8C5C433FE for ; Wed, 23 Nov 2022 09:18:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237446AbiKWJSj (ORCPT ); Wed, 23 Nov 2022 04:18:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237447AbiKWJSK (ORCPT ); Wed, 23 Nov 2022 04:18:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF93B429AF for ; Wed, 23 Nov 2022 01:17:50 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 25F7E61B10 for ; Wed, 23 Nov 2022 09:17:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05B46C433D6; Wed, 23 Nov 2022 09:17:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669195069; bh=d4KiiEoA/FPZHZPhQEpBH1nrt/tnOBHYBbigVyKZEuI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vAEaoAUk0L33zb5DlMGhP+DeiQk9zF2Ft9jdbY4UkudcmOHF63SZDPsBoqOO9NFpe URRk8V7phinnDgcgfynMAEe3TGUVuiYGueAH9GziowwaeurcjcAN1X1c1qivV7TRnY BWVFentcRZ07nh3Xp0+y2L9Awu9Poio/kEfdH3Cc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Andy Shevchenko Subject: [PATCH 5.4 139/156] serial: 8250: Flush DMA Rx on RLSI Date: Wed, 23 Nov 2022 09:51:36 +0100 Message-Id: <20221123084602.926546355@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084557.816085212@linuxfoundation.org> References: <20221123084557.816085212@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ilpo Järvinen commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream. Returning true from handle_rx_dma() without flushing DMA first creates a data ordering hazard. If DMA Rx has handled any character at the point when RLSI occurs, the non-DMA path handles any pending characters jumping them ahead of those characters that are pending under DMA. Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling") Cc: Signed-off-by: Ilpo Järvinen Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1824,10 +1824,9 @@ static bool handle_rx_dma(struct uart_82 if (!up->dma->rx_running) break; fallthrough; + case UART_IIR_RLSI: case UART_IIR_RX_TIMEOUT: serial8250_rx_dma_flush(up); - /* fall-through */ - case UART_IIR_RLSI: return true; } return up->dma->rx_dma(up);