RE: [Intel-wired-lan] [PATCH net] ice: Fix use-after-scope in ice_sched_add_nodes_to_layer()

-----Original Message-----
From: Intel-wired-lan <redacted> On Behalf Of NeKon69
Sent: Saturday, June 13, 2026 12:15 PM
To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel, Przemyslaw <przemyslaw.kitszel@intel.com>
Cc: andrew+netdev@lunn.ch; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; victor.raj@intel.com; intel-wired-lan@lists.osuosl.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; NeKon69 <redacted>
Subject: [Intel-wired-lan] [PATCH net] ice: Fix use-after-scope in ice_sched_add_nodes_to_layer()

Commit 7fb09a737536 ("ice: Modify recursive way of adding nodes") changed ice_sched_add_nodes_to_layer() from recursive control flow to an iterative loop.

Inside the loop, first_teid_ptr may be set to the address of a block-local variable:

u32 temp;
...
if (num_added)
	first_teid_ptr = &temp;

On the next loop iteration, first_teid_ptr may be passed to ice_sched_add_nodes_to_hw_layer(), after temp from the previous iteration has gone out of scope.

Move temp outside the loop so the pointer remains valid for the lifetime of ice_sched_add_nodes_to_layer().

This was found by Clang with LifetimeSafety enabled while testing C language support on a Linux allmodconfig build.

Fixes: 7fb09a737536 ("ice: Modify recursive way of adding nodes")
Link: https://github.com/llvm/llvm-project/pull/203270
Signed-off-by: NeKon69 <redacted>
---
drivers/net/ethernet/intel/ice/ice_sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_sched.c b/drivers/net/ethernet/intel/ice/ice_sched.c
index fff0c1afdb41..089ad3967be5 100644
--- a/drivers/net/ethernet/intel/ice/ice_sched.c
+++ b/drivers/net/ethernet/intel/ice/ice_sched.c

@@ -1074,11 +1074,11 @@ ice_sched_add_nodes_to_layer(struct ice_port_info *pi,

	u32 *first_teid_ptr = first_node_teid;
	u16 new_num_nodes = num_nodes;
	int status = 0;
+	u32 temp;

	*num_nodes_added = 0;
	while (*num_nodes_added < num_nodes) {
		u16 max_child_nodes, num_added = 0;
-		u32 temp;

		status = ice_sched_add_nodes_to_hw_layer(pi, tc_node, parent,
							 layer,	new_num_nodes,
--
2.54.0