diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 70237732a6c7c5f62f941d5df0594f7386ca6a10..f65ab8b014c4f42421d77200243c39c7fd252165 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -214,6 +214,7 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
 		u8 *instr = a->instr;
 		BUG_ON(a->replacementlen > a->instrlen);
 		BUG_ON(a->instrlen > sizeof(insnbuf));
+		BUG_ON(a->cpuid >= NCAPINTS*32);
 		if (!boot_cpu_has(a->cpuid))
 			continue;
 #ifdef CONFIG_X86_64