[PATCH net-next] net: airoha: Grab flow_offload_mutex running airoha_register_gdm_devices()
From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: 2026-03-24 16:55:32
Also in:
linux-arm-kernel, linux-mediatek
Subsystem:
airoha ethernet driver, networking drivers, the rest · Maintainers:
Lorenzo Bianconi, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Netfilter flowtable can theoretically try offload flower rules as soon as a net-device is registered while not all the other ones are registered/initialized, triggering a possible NULL pointer dereferencing of qdma pointer in airoha_ppe_set_cpu_port routine. In order to avoid any possible race, grab the flow_offload_mutex running airoha_register_gdm_devices(). Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> --- drivers/net/ethernet/airoha/airoha_eth.c | 15 +++++++++++---- drivers/net/ethernet/airoha/airoha_eth.h | 2 ++ drivers/net/ethernet/airoha/airoha_ppe.c | 2 +- 3 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 82e53c60f561f6314fbf201ba8bc8711e40edc68..c1476032f78cbac95c9813bbeae6bec2c9c0a685 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c@@ -2943,21 +2943,28 @@ static int airoha_alloc_gdm_port(struct airoha_eth *eth, static int airoha_register_gdm_devices(struct airoha_eth *eth) { - int i; + int i, err = 0; + + /* Netfilter flowtable can try offload flower rules while not all + * the net-devices are registered/initialized. Grab flow_offload_mutex + * to avoid any possible race. + */ + mutex_lock(&flow_offload_mutex); for (i = 0; i < ARRAY_SIZE(eth->ports); i++) { struct airoha_gdm_port *port = eth->ports[i]; - int err; if (!port) continue; err = register_netdev(port->dev); if (err) - return err; + break; } - return 0; + mutex_unlock(&flow_offload_mutex); + + return err; } static int airoha_probe(struct platform_device *pdev)
diff --git a/drivers/net/ethernet/airoha/airoha_eth.h b/drivers/net/ethernet/airoha/airoha_eth.h
index 7df4dbcd8861856c54c2a38bc89c69180ac2f6dc..9d97a54dbfdf9107a10bdb09cf144e5cf1ac9bdb 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.h
+++ b/drivers/net/ethernet/airoha/airoha_eth.h@@ -548,6 +548,8 @@ struct airoha_gdm_port { struct metadata_dst *dsa_meta[AIROHA_MAX_DSA_PORTS]; }; +extern struct mutex flow_offload_mutex; + #define AIROHA_RXD4_PPE_CPU_REASON GENMASK(20, 16) #define AIROHA_RXD4_FOE_ENTRY GENMASK(15, 0)
diff --git a/drivers/net/ethernet/airoha/airoha_ppe.c b/drivers/net/ethernet/airoha/airoha_ppe.c
index 7666b1d2f4f6ea758683181ab90d6fffb7bcd19d..96d092f7214ee3e80843a14528df66cabf79bc58 100644
--- a/drivers/net/ethernet/airoha/airoha_ppe.c
+++ b/drivers/net/ethernet/airoha/airoha_ppe.c@@ -15,7 +15,7 @@ #include "airoha_regs.h" #include "airoha_eth.h" -static DEFINE_MUTEX(flow_offload_mutex); +DEFINE_MUTEX(flow_offload_mutex); static DEFINE_SPINLOCK(ppe_lock); static const struct rhashtable_params airoha_flow_table_params = {
--- base-commit: b1c803d5c8167026791abfaed96fd3e6a1fcd750 change-id: 20260321-airoha-regiser-race-fix-fe854f61d760 Best regards, -- Lorenzo Bianconi [off-list ref]