Commit dd546618 authored by Christian Brauner's avatar Christian Brauner Committed by Linus Torvalds
Browse files

pid: use struct_size_t() helper 



Before commit d67790dd ("overflow: Add struct_size_t() helper") only
struct_size() existed, which expects a valid pointer instance containing
the flexible array.

However, when we determine the default struct pid allocation size for
the associated kmem cache of a pid namespace we need to take the nesting
depth of the pid namespace into account without an variable instance
necessarily being available.

In commit b69f0aeb ("pid: Replace struct pid 1-element array with
flex-array") we used to handle this the old fashioned way and cast NULL
to a struct pid pointer type. However, we do apparently have a dedicated
struct_size_t() helper for exactly this case. So switch to that.

Suggested-by: default avatarKees Cook <keescook@chromium.org>
Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 408579cd

kernel/pid.c

+1 −1
Original line number Diff line number Diff line
@@ -657,7 +657,7 @@ void __init pid_idr_init(void) 
	idr_init(&init_pid_ns.idr);



	init_pid_ns.pid_cachep = kmem_cache_create("pid",

			struct_size((struct pid *)NULL, numbers, 1),

			struct_size_t(struct pid, numbers, 1),

			__alignof__(struct pid),

			SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT,

			NULL);

kernel/pid_namespace.c

+1 −1
Original line number Diff line number Diff line
@@ -48,7 +48,7 @@ static struct kmem_cache *create_pid_cachep(unsigned int level) 
		return kc;



	snprintf(name, sizeof(name), "pid_%u", level + 1);

	len = struct_size((struct pid *)NULL, numbers, level + 1);

	len = struct_size_t(struct pid, numbers, level + 1);

	mutex_lock(&pid_caches_mutex);

	/* Name collision forces to do allocation under mutex. */

	if (!*pkc)