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 457F2C43219 for ; Mon, 21 Nov 2022 11:49:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229645AbiKULtK (ORCPT ); Mon, 21 Nov 2022 06:49:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230410AbiKULtD (ORCPT ); Mon, 21 Nov 2022 06:49:03 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D48622036D for ; Mon, 21 Nov 2022 03:49:02 -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 7BA2C60EC9 for ; Mon, 21 Nov 2022 11:49:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DF3EC433D6; Mon, 21 Nov 2022 11:49:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669031341; bh=ReTFcCQZPhP/psQb/I1rf8RY2UGLFNbepgJYgZ+9oMc=; h=Subject:To:Cc:From:Date:From; b=c3XbWAgx6hLAZLxCdt4XLvyXi+YqWb6HV3VE9S5uk3hn69UXF78sJTlbjTEpWA/D7 VRRmAkj2jUyoNZzOAMPQcZ/pE8QfjuHZ/T3yChHJ54lIOzzH1ElPNjvdDegUq8D9UH b4c3qxPcO8+yn0vRAoTFB6iCW/LbamkC5ogtpHLM= Subject: FAILED: patch "[PATCH] serial: 8250: Flush DMA Rx on RLSI" failed to apply to 5.4-stable tree To: ilpo.jarvinen@linux.intel.com, andriy.shevchenko@linux.intel.com, gregkh@linuxfoundation.org, stable@vger.kernel.org Cc: From: Date: Mon, 21 Nov 2022 12:48:58 +0100 Message-ID: <1669031338112196@kroah.com> 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 The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . Possible dependencies: 1980860e0c82 ("serial: 8250: Flush DMA Rx on RLSI") a931237cbea2 ("serial: 8250: Fall back to non-DMA Rx if IIR_RDI occurs") df561f6688fe ("treewide: Use fallthrough pseudo-keyword") 37711e5e2325 ("Merge tag 'nfs-for-5.9-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 1980860e0c8299316cddaf0992dd9e1258ec9d88 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Tue, 8 Nov 2022 14:19:52 +0200 Subject: [PATCH] serial: 8250: Flush DMA Rx on RLSI MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 92dd18716169..388172289627 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1901,10 +1901,9 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) if (!up->dma->rx_running) break; fallthrough; + case UART_IIR_RLSI: case UART_IIR_RX_TIMEOUT: serial8250_rx_dma_flush(up); - fallthrough; - case UART_IIR_RLSI: return true; } return up->dma->rx_dma(up);