From 34aacb2920667d405a8df15968b7f71ba46c8f18 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Tue, 30 Mar 2010 02:14:26 +0200
Subject: [PATCH] procfs: Use generic_file_llseek in /proc/kcore

/proc/kcore has no llseek and then falls down to use default_llseek.
This is racy against read_kcore() that directly manipulates fpos
but it doesn't hold the bkl there so using it in llseek doesn't
protect anything.

Let's use generic_file_llseek() instead.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: John Kacur <jkacur@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
---
 fs/proc/kcore.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index b442dac8f5f9..396453200ef4 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -557,6 +557,7 @@ static int open_kcore(struct inode *inode, struct file *filp)
 static const struct file_operations proc_kcore_operations = {
 	.read		= read_kcore,
 	.open		= open_kcore,
+	.llseek		= generic_file_llseek,
 };
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-- 
2.30.2