3.16.70-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> commit 201676095dda7e5b31a5e1d116d10fc22985075e upstream. The "cpu" variable comes from the sscanf() so Smatch marks it as untrusted data. We can't pass a higher value than "nr_cpu_ids" to cpu_possible() or it results in an out of bounds access. Fixes: d68d82afd4c8 ("xen: implement CPU hotplugging") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- drivers/xen/cpu_hotplug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/xen/cpu_hotplug.c +++ b/drivers/xen/cpu_hotplug.c @@ -47,7 +47,7 @@ static int vcpu_online(unsigned int cpu) } static void vcpu_hotplug(unsigned int cpu) { - if (!cpu_possible(cpu)) + if (cpu >= nr_cpu_ids || !cpu_possible(cpu)) return; switch (vcpu_online(cpu)) {