[Xen-devel] [PATCH] xen: add assertions in default_vcpu0_location to protect against broken masks

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

When setting up the cpu sibling/etc masks on ARM I accidentally and
incorrectly omitted a CPU from it's own sibling mask which caused this
function to scribble over the heap. Add a couple of asserts to catch this in
the future.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Keir (Xen.org) <keir@xxxxxxx>
Cc: Jan Beulich <JBeulich@xxxxxxxx>
---
 xen/common/domctl.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 9f1a9ad..c1acd1d 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -190,10 +190,12 @@ static unsigned int default_vcpu0_location(cpumask_t 
*online)
      */
     cpumask_copy(&cpu_exclude_map, per_cpu(cpu_sibling_mask, 0));
     cpu = cpumask_first(&cpu_exclude_map);
+    ASSERT(cpu < nr_cpus);
     if ( cpumask_weight(&cpu_exclude_map) > 1 )
         cpu = cpumask_next(cpu, &cpu_exclude_map);
     for_each_cpu(i, online)
     {
+        ASSERT(i < nr_cpus);
         if ( cpumask_test_cpu(i, &cpu_exclude_map) )
             continue;
         if ( (i == cpumask_first(per_cpu(cpu_sibling_mask, i))) &&
-- 
1.7.9.1


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