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[2620:137:e000::1:20]) by mx.google.com with ESMTP id d16-20020a170903231000b0017840d9d42esi16356822plh.582.2022.11.08.04.22.21; Tue, 08 Nov 2022 04:22:33 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@intel.com header.s=Intel header.b=S04avOY4; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234179AbiKHMUg (ORCPT + 99 others); Tue, 8 Nov 2022 07:20:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234153AbiKHMUa (ORCPT ); Tue, 8 Nov 2022 07:20:30 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0795F17A9E; Tue, 8 Nov 2022 04:20:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1667910026; x=1699446026; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=vkqZhcPnjGQqDiDQpqIE/N5L7Qt+GaZklcF5cPF1GxM=; b=S04avOY4z2fnKV5eQWl0ii4kD8D9lSBAvdVDho6Sp2LRdnlQxYIaxhNR VKR0Y6QSg37RtQvWqHGEP/nXVWvJN/OQybpjj1yeJb85HKc26reGl9G9Z oCd5lQ9pKgNI5EVZkhRylc9Dit+qIrZYbywfdvkqXMybaxFo7Zuu0mVe8 4kMRtV1f8OKc9E4swrC3LVnaJFxNtTig1sCl+HP1CP6O519XM+nP9Wjq0 9u17JZnqq6gD0+91fcjTff3Xn44mzNSqeHBQjfwELGEDmo+oRfjcwFR5M CckDC/TJRKKGiX56E1QVQrz82rf2ylyFGRPYnWbqjFTdhC4WHkCOG82Kc g==; X-IronPort-AV: E=McAfee;i="6500,9779,10524"; a="374951476" X-IronPort-AV: E=Sophos;i="5.96,147,1665471600"; d="scan'208";a="374951476" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Nov 2022 04:20:25 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10524"; a="741932231" X-IronPort-AV: E=Sophos;i="5.96,147,1665471600"; d="scan'208";a="741932231" Received: from ppkrause-mobl.ger.corp.intel.com (HELO ijarvine-MOBL2.ger.corp.intel.com) ([10.249.44.73]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Nov 2022 04:20:23 -0800 From: =?utf-8?q?Ilpo_J=C3=A4rvinen?= To: linux-serial@vger.kernel.org, Greg Kroah-Hartman , Jiri Slaby , Andy Shevchenko , Heikki Krogerus , linux-kernel@vger.kernel.org Cc: Gilles BULOZ , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , stable@vger.kernel.org Subject: [PATCH v2 4/4] serial: 8250: Flush DMA Rx on RLSI Date: Tue, 8 Nov 2022 14:19:52 +0200 Message-Id: <20221108121952.5497-5-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221108121952.5497-1-ilpo.jarvinen@linux.intel.com> References: <20221108121952.5497-1-ilpo.jarvinen@linux.intel.com> MIME-Version: 1.0 X-Spam-Status: No, score=-4.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1748930557445205484?= X-GMAIL-MSGID: =?utf-8?q?1748930557445205484?= 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 --- drivers/tty/serial/8250/8250_port.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) 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);