Commit dfbc411e authored by Erick Archer's avatar Erick Archer Committed by Ingo Molnar
Browse files

perf/x86/rapl: Prefer struct_size() over open coded arithmetic 

This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows:

  https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
  https://github.com/KSPP/linux/issues/160



As the "rapl_pmus" variable is a pointer to "struct rapl_pmus" and
this structure ends in a flexible array:

  struct rapl_pmus {
	[...]
	struct rapl_pmu *pmus[] __counted_by(maxdie);
  };

the preferred way in the kernel is to use the struct_size() helper to
do the arithmetic instead of the calculation "size + count * size" in
the kzalloc() function.

This way, the code is more readable and safer.

Signed-off-by: default avatarErick Archer <erick.archer@gmx.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240317164442.6729-1-erick.archer@gmx.com
parent 4ae3dc83

arch/x86/events/rapl.c

+1 −3
Original line number Diff line number Diff line
@@ -675,10 +675,8 @@ static const struct attribute_group *rapl_attr_update[] = { 
static int __init init_rapl_pmus(void)

{

	int maxdie = topology_max_packages() * topology_max_dies_per_package();

	size_t size;



	size = sizeof(*rapl_pmus) + maxdie * sizeof(struct rapl_pmu *);

	rapl_pmus = kzalloc(size, GFP_KERNEL);

	rapl_pmus = kzalloc(struct_size(rapl_pmus, pmus, maxdie), GFP_KERNEL);

	if (!rapl_pmus)

		return -ENOMEM;