linux-kernel - [PATCH] epoll: initialize slack for negative timeout values

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Date:	Wed, 24 Nov 2010 21:31:49 -0600
From:	Shawn Bohrer <shawn.bohrer@...il.com>
To:	Davide Libenzi <davidel@...ilserver.org>
Cc:	Mike Frysinger <vapier.adi@...il.com>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Shawn Bohrer <shawn.bohrer@...il.com>
Subject: [PATCH] epoll: initialize slack for negative timeout values

When a negative timeout value is passed to epoll the 'slack' variable is
currently uninitialized:

fs/eventpoll.c: In function ‘ep_poll’:
fs/eventpoll.c:1119: warning: ‘slack’ may be used uninitialized in this function

In this case a NULL pointer is passed to schedule_hrtimeout_range()
specifying an infinite timeout.  The current implementation of
schedule_hrtimeout_range() does not use slack in this case, but we
should still initialize slack to 0 in case future implementations use it.

Signed-off-by: Shawn Bohrer <shawn.bohrer@...il.com>
---
 fs/eventpoll.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 8cf0724..c24a032 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1116,7 +1116,7 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
 {
 	int res, eavail, timed_out = 0;
 	unsigned long flags;
-	long slack;
+	long slack = 0;
 	wait_queue_t wait;
 	struct timespec end_time;
 	ktime_t expires, *to = NULL;
-- 
1.7.3.2

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