proc: proc_get_inode() should get module only once

Any file under /proc/net opened more than once leaked the refcounter
on the module it belongs to.

The problem is that module_get is called for each file opening while
module_put is called only when /proc inode is destroyed. So, lets put
module counter if we are dealing with already initialised inode.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=10737

Signed-off-by: Denis V. Lunev <den@openvz.org>
Cc: David Miller <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Robert Olsson <robert.olsson@its.uu.se>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Reported-by: Roland Kletzing <devzero@web.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 6f4e8dc97da1..b08d10017911 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -425,7 +425,8 @@ struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
                         }
                 }
                 unlock_new_inode(inode);
-        }
+        } else
+               module_put(de->owner);
         return inode;
 
 out_ino: