[3.13.y-ckt stable] Patch "posix-clock: Fix return code on the poll method's error path" has been added to the 3.13.y-ckt tree
Kamal Mostafa
kamal at canonical.com
Tue Feb 2 00:35:02 UTC 2016
This is a note to let you know that I have just added a patch titled
posix-clock: Fix return code on the poll method's error path
to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue
This patch is scheduled to be released in version 3.13.11-ckt34.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From a6a09855d5faf6af3c2d3e15ce0af89bba615b49 Mon Sep 17 00:00:00 2001
From: Richard Cochran <richardcochran at gmail.com>
Date: Tue, 22 Dec 2015 22:19:58 +0100
Subject: posix-clock: Fix return code on the poll method's error path
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 <elfring at users.sourceforge.net>
igned-off-by: Richard Cochran <richardcochran at gmail.com>
Cc: John Stultz <john.stultz at linaro.org>
Cc: Julia Lawall <julia.lawall at lip6.fr>
Link: http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcochran@gmail.com
Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
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 ce033c7..9cff0ab 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);
--
1.9.1
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