arm64: kexec_file: Use struct_size() in kmalloc()

Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes.

This code was detected with the help of Coccinelle and, audited and fixed manually.

---
 arch/arm64/kernel/machine_kexec_file.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

index 522e6f517ec0..361a1143e09e 100644
@@ -219,8 +219,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
 					MEMBLOCK_NONE, &start, &end, NULL)
 		nr_ranges++;
 
-	cmem = kmalloc(sizeof(struct crash_mem) +
-			sizeof(struct crash_mem_range) * nr_ranges, GFP_KERNEL);
+	cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
 	if (!cmem)
 		return -ENOMEM;
 

2.27.0

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64: kexec_file: Use struct_size() in kmalloc()

      https://git.kernel.org/arm64/c/bf508ec95ca3

Cheers,

Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev