From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1733193-1527156349-2-4570198488051568750 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1527156348; b=IqyVGzJRnDdYZuj/ADQ+ywkq892HA6fkGwGkoinRUZ6s7YImEw E/0b3mQbiVdwQNrLSjZP6XD2Z9gxMWsOalYLFYTjPyuxFcF/zSayQvDu+r+Ut6Vq HPD90vrkWkQxczfJFd4vB1wg4fGc0w5UobhQ6g+9b0itmfr5MZTPQQgXg3Gs+ZIS R9Mp8YSJBKPN+U3/sqGt/S1P+uqRst9ZwG6dH8BvrMTZ98/cLo/swf657AihqpHO 0+EQsUKhJBTbwsej9C4oRPOcdXAiGPTvy3DbCwATWRxH1WdApi4bAQd71xepZfZs etf5rYgRg7yFeJh8CRNrazARuGqqJvuLdJsA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1527156348; bh=zWzLfT54AEQrB4r2ZLxouDCie7JntE Wrw5KbV51aii8=; b=GO/Drnfaw0YK7lLBsqM3QGWNCeLO7ayWw8l1oY4NGtvwfV guiAyk5hScdhEUuPN7WdLMgzKapXMQPoXOIgkAKaxM5i0Al+DcBBXIp85NzZA0yB HGTvBfSyS4Gh/Cghq9qn9irMqVPkB3R95z45mGnwfcMQdjBOFM7EaZOyKhvUdS04 m7ni0uJpB5uCsJg4/BA6DVrJDEbObltYMmrEa6u/ufifbzIrsT1Bc7VNx8YIIAZu xIp6GfXW+hzxF2Xu87GstOyVki2ov3ZnB8OhYS04X5lAlSMZvG6ObzIZi7dbywju fbAJyx92KVLfW7cdVXM8urUndC6UbIbSCLE0dzPw== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=ykX7RU9m x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=ykX7RU9m x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfMJo6LlJRdFaKU9Grufx/shfcmhMwHJGABp9txHgIf+OIPDZNZJId3vQ3bMMZnsqWaTielOmA9CRq5TR++4z94mK2kZIU20x5aB0I0CenBrmuralSSBL gOPkTp//FkI8+Ra1arYcPMGZ5mx0ZTg/LoioesfKxRwNIHqG2ANB3VupZv18yXiZq4yOkpragQwQJnhaSnPcXAuKT4IFqHEG3uSMNhTJ4rpbfdxMsZ4aV3L5 X-CM-Analysis: v=2.3 cv=E8HjW5Vl c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=sozttTNsAAAA:8 a=yMhMjlubAAAA:8 a=ag1SF4gXAAAA:8 a=detmJ2bfGwl12fOR2OwA:9 a=QEXdDO2ut3YA:10 a=aeg5Gbbo78KNqacMgKqU:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031315AbeEXKFp (ORCPT ); Thu, 24 May 2018 06:05:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:54824 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031229AbeEXKFn (ORCPT ); Thu, 24 May 2018 06:05:43 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vignesh R , Sasha Levin Subject: [PATCH 4.16 153/161] serial: 8250: Dont service RX FIFO if interrupts are disabled Date: Thu, 24 May 2018 11:39:38 +0200 Message-Id: <20180524093036.547964383@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180524093018.331893860@linuxfoundation.org> References: <20180524093018.331893860@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vignesh R [ Upstream commit 2e9fe539108320820016f78ca7704a7342788380 ] Currently, data in RX FIFO is read based on UART_LSR register state even if RDI and RLSI interrupts are disabled in UART_IER register. This is because when IRQ handler is called due to TX FIFO empty event, RX FIFO is serviced based on UART_LSR register status instead of UART_IIR status. This defeats the purpose of disabling UART RX FIFO interrupts during throttling(see, omap_8250_throttle()) as IRQ handler continues to drain UART RX FIFO resulting in overflow of buffer at tty layer. Fix this by making sure that driver drains UART RX FIFO only when UART_IIR_RDI is set along with UART_LSR_BI or UART_LSR_DR bits. Signed-off-by: Vignesh R Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_port.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1867,7 +1867,8 @@ int serial8250_handle_irq(struct uart_po status = serial_port_in(port, UART_LSR); - if (status & (UART_LSR_DR | UART_LSR_BI)) { + if (status & (UART_LSR_DR | UART_LSR_BI) && + iir & UART_IIR_RDI) { if (!up->dma || handle_rx_dma(up, iir)) status = serial8250_rx_chars(up, status); }