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Wed, 08 Jul 2026 04:30:30 -0700 (PDT) Received: from [127.0.1.1] ([47.253.114.73]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ccc9bdb877sm26691105ad.14.2026.07.08.04.30.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Jul 2026 04:30:30 -0700 (PDT) From: Wayen Yan To: netdev@vger.kernel.org Cc: lorenzo@kernel.org, horms@kernel.org, pabeni@redhat.com, kuba@kernel.org, edumazet@google.com, andrew+netdev@lunn.ch, angelogioacchino.delregno@collabora.com, matthias.bgg@gmail.com, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: [PATCH net] net: airoha: Fix potential use-after-free in airoha_ppe_deinit() Date: Wed, 8 Jul 2026 19:16:16 +0800 Message-ID: <178351022574.97989.6880403520276841703@gmail.com> Content-Type: text/plain; charset=utf-8 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260708_043032_158589_26F02019 X-CRM114-Status: GOOD ( 10.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 --- 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); } -- 2.51.0