Created attachment 276375 [details] [review]
Avoid Possible null pointer dereference in trio.c

In file :
https://git.gnome.org/browse/libxml2/tree/trio.c

TRIO_PRIVATE void
TrioInStreamFile
TRIO_ARGS2((self, intPointer),
	   trio_class_t *self,
	   int *intPointer)
{
  FILE *file = (FILE *)self->location;

  assert(VALID(self));
  assert(VALID(file));


and 

TRIO_PRIVATE void
TrioInStreamFileDescriptor
TRIO_ARGS2((self, intPointer),
	   trio_class_t *self,
	   int *intPointer)
{
  int fd = *((int *)self->location);
  int size;
  unsigned char input;

  assert(VALID(self));



self is dereferenced before NULL check and  hence may create crash scenario.

Please apply attached patch.