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 <[email protected]>
Cc: David Miller <[email protected]>
Cc: Patrick McHardy <[email protected]>
Acked-by: Pavel Emelyanov <[email protected]>
Acked-by: Robert Olsson <[email protected]>
Acked-by: Eric W. Biederman <[email protected]>
Reported-by: Roland Kletzing <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 6f4e8dc97da1f24f6313b4425efa323fe82a644c..b08d10017911f43927646943307e26238e4fe7dc 100644 (file)
--- 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: