Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932749AbcDDX2X (ORCPT ); Mon, 4 Apr 2016 19:28:23 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:35098 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932703AbcDDX2Q (ORCPT ); Mon, 4 Apr 2016 19:28:16 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Max Filippov , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 42/97] xtensa: ISS: don't hang if stdin EOF is reached Date: Mon, 4 Apr 2016 16:26:06 -0700 Message-Id: <1459812421-933-43-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1459812421-933-1-git-send-email-kamal@canonical.com> References: <1459812421-933-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1555 Lines: 54 3.13.11-ckt38 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ 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: Kamal Mostafa --- arch/xtensa/platforms/iss/console.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/xtensa/platforms/iss/console.c b/arch/xtensa/platforms/iss/console.c index 70cb408..92d785f 100644 --- 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); } -- 2.7.4