lguest: dereferencing freed mem in add_eventfd()

"new" was freed and then dereferenced.  Also the return value wasn't being
used so I modified the caller as well.

Compile tested only.  Found by smatch (http://repo.or.cz/w/smatch.git).

regards,
dan carpenter

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index 9f9a2953b383..407722a8e0c4 100644
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -52,8 +52,9 @@ static int add_eventfd(struct lguest *lg, unsigned long addr, int fd)
         new->map[new->num].addr = addr;
         new->map[new->num].event = eventfd_ctx_fdget(fd);
         if (IS_ERR(new->map[new->num].event)) {
+                int err =  PTR_ERR(new->map[new->num].event);
                 kfree(new);
-                return PTR_ERR(new->map[new->num].event);
+                return err;
         }
         new->num++;
 
@@ -83,7 +84,7 @@ static int attach_eventfd(struct lguest *lg, const unsigned long __user *input)
         err = add_eventfd(lg, addr, fd);
         mutex_unlock(&lguest_lock);
 
-        return 0;
+        return err;
 }
 
 /*L:050 Sending an interrupt is done by writing LHREQ_IRQ and an interrupt