Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754888AbcD0ABA (ORCPT ); Tue, 26 Apr 2016 20:01:00 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:40341 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754085AbcDZXOH (ORCPT ); Tue, 26 Apr 2016 19:14:07 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Max Filippov" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 089/217] xtensa: ISS: don't hang if stdin EOF is reached In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1371 Lines: 50 3.16.35-rc1 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: Ben Hutchings --- 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); }