References: bnc#842514 CVE-2013-4371 XSA-70

# Commit 4c37ed562224295c0f8b00211287d57cae629782
# Date 2013-10-10 15:49:54 +0100
# Author Matthew Daley <mattjd@gmail.com>
# Committer Ian Jackson <Ian.Jackson@eu.citrix.com>
libxl: fix out-of-memory error handling in libxl_list_cpupool

...otherwise it will return freed memory. All the current users of this
function check already for a NULL return, so use that.

Coverity-ID: 1056194

This is CVE-2013-4371 / XSA-70

Signed-off-by: Matthew Daley <mattjd@gmail.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -649,6 +649,7 @@ libxl_cpupoolinfo * libxl_list_cpupool(l
         if (!tmp) {
             LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "allocating cpupool info");
             libxl_cpupoolinfo_list_free(ptr, i);
+            ptr = NULL;
             goto out;
         }
         ptr = tmp;