From ff61b5e3f041c2f1aa8d7c700af3007889973889 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 20 Oct 2017 10:23:37 +0300 Subject: drivers, net, mlx4: convert mlx4_cq.refcount from atomic_t to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable mlx4_cq.refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: David S. Miller --- include/linux/mlx4/device.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h index b0a57e043fa3..daac2e3a1a58 100644 --- a/include/linux/mlx4/device.h +++ b/include/linux/mlx4/device.h @@ -40,7 +40,7 @@ #include #include -#include +#include #include @@ -751,7 +751,7 @@ struct mlx4_cq { int cqn; unsigned vector; - atomic_t refcount; + refcount_t refcount; struct completion free; struct { struct list_head list; -- cgit v1.2.3-59-g8ed1b