6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jinjian Song jinjian.song@fibocom.com
[ Upstream commit 905fe0845bb27e4eed2ca27ea06e6c4847f1b2b1 ]
When driver handles the napi rx polling requests, the netdev might have been released by the dellink logic triggered by the disconnect operation on user plane. However, in the logic of processing skb in polling, an invalid netdev is still being used, which causes a panic.
BUG: kernel NULL pointer dereference, address: 00000000000000f1 Oops: 0000 [#1] PREEMPT SMP NOPTI RIP: 0010:dev_gro_receive+0x3a/0x620 [...] Call Trace: <IRQ> ? __die_body+0x68/0xb0 ? page_fault_oops+0x379/0x3e0 ? exc_page_fault+0x4f/0xa0 ? asm_exc_page_fault+0x22/0x30 ? __pfx_t7xx_ccmni_recv_skb+0x10/0x10 [mtk_t7xx (HASH:1400 7)] ? dev_gro_receive+0x3a/0x620 napi_gro_receive+0xad/0x170 t7xx_ccmni_recv_skb+0x48/0x70 [mtk_t7xx (HASH:1400 7)] t7xx_dpmaif_napi_rx_poll+0x590/0x800 [mtk_t7xx (HASH:1400 7)] net_rx_action+0x103/0x470 irq_exit_rcu+0x13a/0x310 sysvec_apic_timer_interrupt+0x56/0x90 </IRQ>
Fixes: 5545b7b9f294 ("net: wwan: t7xx: Add NAPI support") Signed-off-by: Jinjian Song jinjian.song@fibocom.com Link: https://patch.msgid.link/20250530031648.5592-1-jinjian.song@fibocom.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wwan/t7xx/t7xx_netdev.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wwan/t7xx/t7xx_netdev.c b/drivers/net/wwan/t7xx/t7xx_netdev.c index 91fa082e9cab8..fc0a7cb181df2 100644 --- a/drivers/net/wwan/t7xx/t7xx_netdev.c +++ b/drivers/net/wwan/t7xx/t7xx_netdev.c @@ -302,7 +302,7 @@ static int t7xx_ccmni_wwan_newlink(void *ctxt, struct net_device *dev, u32 if_id ccmni->ctlb = ctlb; ccmni->dev = dev; atomic_set(&ccmni->usage, 0); - ctlb->ccmni_inst[if_id] = ccmni; + WRITE_ONCE(ctlb->ccmni_inst[if_id], ccmni);
ret = register_netdevice(dev); if (ret) @@ -324,6 +324,7 @@ static void t7xx_ccmni_wwan_dellink(void *ctxt, struct net_device *dev, struct l if (WARN_ON(ctlb->ccmni_inst[if_id] != ccmni)) return;
+ WRITE_ONCE(ctlb->ccmni_inst[if_id], NULL); unregister_netdevice(dev); }
@@ -419,7 +420,7 @@ static void t7xx_ccmni_recv_skb(struct t7xx_ccmni_ctrl *ccmni_ctlb, struct sk_bu
skb_cb = T7XX_SKB_CB(skb); netif_id = skb_cb->netif_idx; - ccmni = ccmni_ctlb->ccmni_inst[netif_id]; + ccmni = READ_ONCE(ccmni_ctlb->ccmni_inst[netif_id]); if (!ccmni) { dev_kfree_skb(skb); return; @@ -441,7 +442,7 @@ static void t7xx_ccmni_recv_skb(struct t7xx_ccmni_ctrl *ccmni_ctlb, struct sk_bu
static void t7xx_ccmni_queue_tx_irq_notify(struct t7xx_ccmni_ctrl *ctlb, int qno) { - struct t7xx_ccmni *ccmni = ctlb->ccmni_inst[0]; + struct t7xx_ccmni *ccmni = READ_ONCE(ctlb->ccmni_inst[0]); struct netdev_queue *net_queue;
if (netif_running(ccmni->dev) && atomic_read(&ccmni->usage) > 0) { @@ -453,7 +454,7 @@ static void t7xx_ccmni_queue_tx_irq_notify(struct t7xx_ccmni_ctrl *ctlb, int qno
static void t7xx_ccmni_queue_tx_full_notify(struct t7xx_ccmni_ctrl *ctlb, int qno) { - struct t7xx_ccmni *ccmni = ctlb->ccmni_inst[0]; + struct t7xx_ccmni *ccmni = READ_ONCE(ctlb->ccmni_inst[0]); struct netdev_queue *net_queue;
if (atomic_read(&ccmni->usage) > 0) { @@ -471,7 +472,7 @@ static void t7xx_ccmni_queue_state_notify(struct t7xx_pci_dev *t7xx_dev, if (ctlb->md_sta != MD_STATE_READY) return;
- if (!ctlb->ccmni_inst[0]) { + if (!READ_ONCE(ctlb->ccmni_inst[0])) { dev_warn(&t7xx_dev->pdev->dev, "No netdev registered yet\n"); return; }