Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759433AbcCDJVo (ORCPT ); Fri, 4 Mar 2016 04:21:44 -0500 Received: from mx2.suse.de ([195.135.220.15]:59675 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759057AbcCDJDl (ORCPT ); Fri, 4 Mar 2016 04:03:41 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Richard Cochran , John Stultz , Julia Lawall , Thomas Gleixner , Jiri Slaby Subject: [PATCH 3.12 087/116] posix-clock: Fix return code on the poll method's error path Date: Fri, 4 Mar 2016 10:02:12 +0100 Message-Id: X-Mailer: git-send-email 2.7.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1902 Lines: 52 From: Richard Cochran 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 1b9f23727abb92c5e58f139e7d180befcaa06fe0 upstream. The posix_clock_poll function is supposed to return a bit mask of POLLxxx values. However, in case the hardware has disappeared (due to hot plugging for example) this code returns -ENODEV in a futile attempt to throw an error at the file descriptor level. The kernel's file_operations interface does not accept such error codes from the poll method. Instead, this function aught to return POLLERR. The value -ENODEV does, in fact, contain the POLLERR bit (and almost all the other POLLxxx bits as well), but only by chance. This patch fixes code to return a proper bit mask. Credit goes to Markus Elfring for pointing out the suspicious signed/unsigned mismatch. Reported-by: Markus Elfring igned-off-by: Richard Cochran Cc: John Stultz Cc: Julia Lawall Link: http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcochran@gmail.com Signed-off-by: Thomas Gleixner Signed-off-by: Jiri Slaby --- kernel/time/posix-clock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c index ce033c7aa2e8..9cff0ab82b63 100644 --- a/kernel/time/posix-clock.c +++ b/kernel/time/posix-clock.c @@ -69,10 +69,10 @@ static ssize_t posix_clock_read(struct file *fp, char __user *buf, static unsigned int posix_clock_poll(struct file *fp, poll_table *wait) { struct posix_clock *clk = get_posix_clock(fp); - int result = 0; + unsigned int result = 0; if (!clk) - return -ENODEV; + return POLLERR; if (clk->ops.poll) result = clk->ops.poll(clk, fp, wait); -- 2.7.2