4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> commit 421b8f20d3c381b215f988b42428f56fc3b82405 upstream. It may happen that not all CPUs are online when we do hv_synic_alloc() and in case more CPUs come online later we may try accessing these allocated structures. Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hv/hv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -411,7 +411,7 @@ int hv_synic_alloc(void) goto err; } - for_each_online_cpu(cpu) { + for_each_present_cpu(cpu) { hv_context.event_dpc[cpu] = kmalloc(size, GFP_ATOMIC); if (hv_context.event_dpc[cpu] == NULL) { pr_err("Unable to allocate event dpc\n"); @@ -482,7 +482,7 @@ void hv_synic_free(void) int cpu; kfree(hv_context.hv_numa_map); - for_each_online_cpu(cpu) + for_each_present_cpu(cpu) hv_synic_free_cpu(cpu); }