From 67b8046f42f81aecfca97b50ec3b398bb0ee8e97 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Tue, 5 Mar 2019 15:44:05 -0800 Subject: [PATCH] mm/memcontrol.c: use struct_size() in kmalloc() One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Link: http://lkml.kernel.org/r/20190104183726.GA6374@embeddedor Signed-off-by: Gustavo A. R. Silva Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 72414bb7e226..f93f7f22a6f4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3626,8 +3626,7 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg, size = thresholds->primary ? thresholds->primary->size + 1 : 1; /* Allocate memory for new array of thresholds */ - new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), - GFP_KERNEL); + new = kmalloc(struct_size(new, entries, size), GFP_KERNEL); if (!new) { ret = -ENOMEM; goto unlock; -- 2.30.2