From 2484568a335cd7bda951c75b3a7d95ea36161ae7 Mon Sep 17 00:00:00 2001 From: Wayen Yan Date: Wed, 8 Jul 2026 19:16:16 +0800 Subject: [PATCH] net: airoha: Fix potential use-after-free in airoha_ppe_deinit() airoha_ppe_deinit() replaces the NPU pointer with NULL via rcu_replace_pointer() but does not wait for existing RCU readers to exit before calling ppe_deinit() and airoha_npu_put(). This can cause a use-after-free if a reader in an RCU read-side critical section still holds a reference to the NPU when it is freed. The init path (airoha_ppe_init) already calls synchronize_rcu() after rcu_assign_pointer(), but the deinit path introduced in commit 6abcf751bc08 ("net: airoha: Fix schedule while atomic in airoha_ppe_deinit()") omitted the matching barrier when switching from rcu_read_lock()/rcu_dereference() to rcu_replace_pointer(). Add synchronize_rcu() before ppe_deinit() to ensure all existing RCU readers have completed before the NPU resources are released. Fixes: 6abcf751bc084804a9e5b3051442e8a2ce67f48a ("net: airoha: Fix schedule while atomic in airoha_ppe_deinit()") Signed-off-by: Wayen Yan Acked-by: Lorenzo Bianconi Link: https://patch.msgid.link/178351022574.97989.6880403520276841703@gmail.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/airoha/airoha_ppe.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/ethernet/airoha/airoha_ppe.c b/drivers/net/ethernet/airoha/airoha_ppe.c index e7c78293002a..f6396925722d 100644 --- a/drivers/net/ethernet/airoha/airoha_ppe.c +++ b/drivers/net/ethernet/airoha/airoha_ppe.c @@ -1659,6 +1659,7 @@ void airoha_ppe_deinit(struct airoha_eth *eth) npu = rcu_replace_pointer(eth->npu, NULL, lockdep_is_held(&flow_offload_mutex)); if (npu) { + synchronize_rcu(); npu->ops.ppe_deinit(npu); airoha_npu_put(npu); }