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KVM: correct error-handling code

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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>
This commit is contained in:
Julia Lawall 2009-07-28 17:53:24 +02:00 committed by Avi Kivity
parent 28bcb11218
commit 6223011fb9
1 changed files with 1 additions and 1 deletions
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2
virt/kvm/eventfd.c
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@ -230,7 +230,7 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
if (eventfd && !IS_ERR(eventfd)) if (eventfd && !IS_ERR(eventfd))
eventfd_ctx_put(eventfd); eventfd_ctx_put(eventfd);
if (file && !IS_ERR(file)) if (!IS_ERR(file))
fput(file); fput(file);
kfree(irqfd); kfree(irqfd);