commit 6223011fb9f90fab92635f1f782196cbd2ccf24f
author Julia Lawall <julia@diku.dk> Tue Jul 28 17:53:24 2009 +0200
committer Avi Kivity <avi@redhat.com> Thu Sep 10 18:11:12 2009 +0300
tree 61a7c3c2ef16c66187df99b7258eadf976a096c2
parent 28bcb112183cb822a394b155a2e7d788fe4a109a

KVM: correct error-handling code

This code is not executed before file has been initialized to the result of
calling eventfd_fget.  This function returns an ERR_PTR value in an error
case instead of NULL.  Thus the test that file is not NULL is always true.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@match exists@
expression x, E;
statement S1, S2;
@@

x = eventfd_fget(...)
... when != x = E
(
*  if (x == NULL || ...) S1 else S2
|
*  if (x == NULL && ...) S1 else S2
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Avi Kivity <avi@redhat.com>