diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index f631a3f155875bfad8b8e709364a1e5c38706e24..91b3483e5085f3317703e77903522554e351d548 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -356,7 +356,7 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 	struct crash_memmap_data cmd;
 	struct crash_mem *cmem;
 
-	cmem = vzalloc(sizeof(struct crash_mem));
+	cmem = vzalloc(struct_size(cmem, ranges, 1));
 	if (!cmem)
 		return -ENOMEM;