Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752971AbcDJTup (ORCPT ); Sun, 10 Apr 2016 15:50:45 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:53950 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932582AbcDJTIx (ORCPT ); Sun, 10 Apr 2016 15:08:53 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Max Filippov Subject: [PATCH 4.4 137/210] xtensa: ISS: dont hang if stdin EOF is reached Date: Sun, 10 Apr 2016 11:35:58 -0700 Message-Id: <20160410183531.490188696@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160410183526.651820045@linuxfoundation.org> References: <20160410183526.651820045@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1386 Lines: 52 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Max Filippov commit 362014c8d9d51d504c167c44ac280169457732be upstream. Simulator stdin may be connected to a file, when its end is reached kernel hangs in infinite loop inside rs_poll, because simc_poll always signals that descriptor 0 is readable and simc_read always returns 0. Check simc_read return value and exit loop if it's not positive. Also don't rewind polling timer if it's zero. Signed-off-by: Max Filippov Signed-off-by: Greg Kroah-Hartman --- arch/xtensa/platforms/iss/console.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/arch/xtensa/platforms/iss/console.c +++ b/arch/xtensa/platforms/iss/console.c @@ -100,21 +100,23 @@ static void rs_poll(unsigned long priv) { struct tty_port *port = (struct tty_port *)priv; int i = 0; + int rd = 1; unsigned char c; spin_lock(&timer_lock); while (simc_poll(0)) { - simc_read(0, &c, 1); + rd = simc_read(0, &c, 1); + if (rd <= 0) + break; tty_insert_flip_char(port, c, TTY_NORMAL); i++; } if (i) tty_flip_buffer_push(port); - - - mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE); + if (rd) + mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE); spin_unlock(&timer_lock); }