On some arch (for example IPQ8074) and other with KERNEL_STACKPROTECTOR_STRONG enabled, the following compilation error is triggered: drivers/net/wireguard/allowedips.c: In function 'root_remove_peer_lists': drivers/net/wireguard/allowedips.c:80:1: error: the frame size of 1040 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] 80 | } | ^ drivers/net/wireguard/allowedips.c: In function 'root_free_rcu': drivers/net/wireguard/allowedips.c:67:1: error: the frame size of 1040 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] 67 | } | ^ cc1: all warnings being treated as errors

Since these are free function and returns void, using function that can fail is not ideal since an error would result in data not freed. Since the free are under RCU lock, we can allocate the required stack array as static outside the function and memset when needed. This effectively fix the stack frame warning without changing how the function work.

Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Signed-off-by: Christian Marangi ansuelsmth@gmail.com Cc: stable@vger.kernel.org ---

Changes v2: - Fix double Fixes in fixes tag

drivers/net/wireguard/allowedips.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c index 5bf7822c53f1..c129082f04c6 100644 --- a/drivers/net/wireguard/allowedips.c +++ b/drivers/net/wireguard/allowedips.c @@ -53,12 +53,16 @@ static void node_free_rcu(struct rcu_head *rcu) kmem_cache_free(node_cache, container_of(rcu, struct allowedips_node, rcu)); }

+static struct allowedips_node *tmpstack[MAX_ALLOWEDIPS_BITS]; + static void root_free_rcu(struct rcu_head *rcu) { - struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_BITS] = { - container_of(rcu, struct allowedips_node, rcu) }; + struct allowedips_node *node, **stack = tmpstack; unsigned int len = 1;

+ memset(stack, 0, sizeof(*stack) * MAX_ALLOWEDIPS_BITS); + stack[0] = container_of(rcu, struct allowedips_node, rcu); + while (len > 0 && (node = stack[--len])) { push_rcu(stack, node->bit[0], &len); push_rcu(stack, node->bit[1], &len); @@ -68,9 +72,12 @@ static void root_free_rcu(struct rcu_head *rcu)

static void root_remove_peer_lists(struct allowedips_node *root) { - struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_BITS] = { root }; + struct allowedips_node *node, **stack = tmpstack; unsigned int len = 1;

+ memset(stack, 0, sizeof(*stack) * MAX_ALLOWEDIPS_BITS); + stack[0] = root; + while (len > 0 && (node = stack[--len])) { push_rcu(stack, node->bit[0], &len); push_rcu(stack, node->bit[1], &len);