The qdisc offload callbacks invoked by stmmac_setup_tc() program MTL/MAC registers, but they can be reached while the interface is down, when stmmac_release() has dropped the runtime PM usage counter and the device may be suspended with its clocks gated. Accessing the registers in that state can trigger a bus error. Hold a runtime PM reference while configuring the register-touching qdisc offloads (mqprio, cbs and taprio) so the device is active, and its clocks enabled, whenever the MTL/MAC registers are programmed. The TC block callback stmmac_setup_tc_block_cb() programs the MTL/MAC registers as well, but it runs asynchronously from stmmac_setup_tc(), outside the runtime PM reference held there. Hold a runtime PM reference for the whole stmmac_setup_tc_block_cb() call as well, covering the cls_u32/cls_flower setup and the queue enable/disable accesses. No reference is held for the TC_SETUP_BLOCK bookkeeping itself, the TC_QUERY_CAPS query or the tc-etf path, since none of them touch the registers synchronously. In particular the block bind/unbind must reach flow_block_cb_setup_simple() even when the device is suspended, so the driver never leaves a stale flow_block_cb on its block list. Fixes: 1f705bc61aee ("net: stmmac: Add support for CBS QDISC") Fixes: 4dbbe8dde848 ("net: stmmac: Add support for U32 TC filter using Flexible RX Parser") Signed-off-by: Lorenzo Bianconi --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 34 ++++++++++++++++++++--- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index b2b7d0242dd3..4baf40fb01dc 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -6392,9 +6392,13 @@ static int stmmac_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv) { struct stmmac_priv *priv = cb_priv; - int ret = -EOPNOTSUPP; + int ret; if (!tc_cls_can_offload_and_chain0(priv->dev, type_data)) + return -EOPNOTSUPP; + + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) return ret; __stmmac_disable_all_queues(priv); @@ -6411,6 +6415,8 @@ static int stmmac_setup_tc_block_cb(enum tc_setup_type type, void *type_data, } stmmac_enable_all_queues(priv); + pm_runtime_put(priv->device); + return ret; } @@ -6420,26 +6426,46 @@ static int stmmac_setup_tc(struct net_device *ndev, enum tc_setup_type type, void *type_data) { struct stmmac_priv *priv = netdev_priv(ndev); + int ret; switch (type) { case TC_QUERY_CAPS: return stmmac_tc_query_caps(priv, priv, type_data); case TC_SETUP_QDISC_MQPRIO: - return stmmac_tc_setup_mqprio(priv, priv, type_data); + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) + return ret; + + ret = stmmac_tc_setup_mqprio(priv, priv, type_data); + break; case TC_SETUP_BLOCK: return flow_block_cb_setup_simple(type_data, &stmmac_block_cb_list, stmmac_setup_tc_block_cb, priv, priv, true); case TC_SETUP_QDISC_CBS: - return stmmac_tc_setup_cbs(priv, priv, type_data); + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) + return ret; + + ret = stmmac_tc_setup_cbs(priv, priv, type_data); + break; case TC_SETUP_QDISC_TAPRIO: - return stmmac_tc_setup_taprio(priv, priv, type_data); + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) + return ret; + + ret = stmmac_tc_setup_taprio(priv, priv, type_data); + break; case TC_SETUP_QDISC_ETF: return stmmac_tc_setup_etf(priv, priv, type_data); default: return -EOPNOTSUPP; } + + pm_runtime_put(priv->device); + + return ret; } static u16 stmmac_select_queue(struct net_device *dev, struct sk_buff *skb, --- base-commit: 7cbfb180945ce529608e4d4e24a6d483699fab1e change-id: 20260824-stmmac-setup-tc-enable-pm-149aa563d797 Best regards, -- Lorenzo Bianconi