[Xen-devel] [PATCH 21/21] xen: add assertion 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 return an invalid cpu number which caused errors later when we
tried to access per_cpu data for that invalid cpu.

Add an assert to catch this in the future.

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

diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 9f1a9ad..7ca6b08 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -192,6 +192,7 @@ static unsigned int default_vcpu0_location(cpumask_t 
*online)
     cpu = cpumask_first(&cpu_exclude_map);
     if ( cpumask_weight(&cpu_exclude_map) > 1 )
         cpu = cpumask_next(cpu, &cpu_exclude_map);
+    ASSERT(cpu < nr_cpu_ids);
     for_each_cpu(i, online)
     {
         if ( cpumask_test_cpu(i, &cpu_exclude_map) )
-- 
1.7.9.1


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