net: wwan: t7xx: Fix napi rx poll issue

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: wwan: t7xx: Fix napi rx poll issue 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>

References

• https://git.kernel.org/stable/c/cc89f457d9133a558d4e8ef26dc20843c2d12073
• https://git.kernel.org/stable/c/e2df04e69c3f10b412f54be036dd0ed3b14756cf
• https://git.kernel.org/stable/c/66542e9430c625f878a5b5dc0fe41e3458d614bf
• https://git.kernel.org/stable/c/905fe0845bb27e4eed2ca27ea06e6c4847f1b2b1