In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm: fix warning when handle discover_identity message Since both source and sink device can send discover_identity message in PD3, kernel may dump below warning: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 169 at drivers/usb/typec/tcpm/tcpm.c:1446 tcpm_queue_vdm+0xe0/0xf0 Modules linked in: CPU: 0 PID: 169 Comm: 1-0050 Not tainted 6.1.1-00038-g6a3c36cf1da2-dirty #567 Hardware name: NXP i.MX8MPlus EVK board (DT) pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : tcpm_queue_vdm+0xe0/0xf0 lr : tcpm_queue_vdm+0x2c/0xf0 sp : ffff80000c19bcd0 x29: ffff80000c19bcd0 x28: 0000000000000001 x27: ffff0000d11c8ab8 x26: ffff0000d11cc000 x25: 0000000000000000 x24: 00000000ff008081 x23: 0000000000000001 x22: 00000000ff00a081 x21: ffff80000c19bdbc x20: 0000000000000000 x19: ffff0000d11c8080 x18: ffffffffffffffff x17: 0000000000000000 x16: 0000000000000000 x15: ffff0000d716f580 x14: 0000000000000001 x13: ffff0000d716f507 x12: 0000000000000001 x11: 0000000000000000 x10: 0000000000000020 x9 : 00000000000ee098 x8 : 00000000ffffffff x7 : 000000000000001c x6 : ffff0000d716f580 x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 x2 : ffff80000c19bdbc x1 : 00000000ff00a081 x0 : 0000000000000004 Call trace: tcpm_queue_vdm+0xe0/0xf0 tcpm_pd_rx_handler+0x340/0x1ab0 kthread_worker_fn+0xcc/0x18c kthread+0x10c/0x110 ret_from_fork+0x10/0x20 ---[ end trace 0000000000000000 ]--- Below sequences may trigger this warning: tcpm_send_discover_work(work) tcpm_send_vdm(port, USB_SID_PD, CMD_DISCOVER_IDENT, NULL, 0); tcpm_queue_vdm(port, header, data, count); port->vdm_state = VDM_STATE_READY; vdm_state_machine_work(work); <-- received discover_identity from partner vdm_run_state_machine(port); port->vdm_state = VDM_STATE_SEND_MESSAGE; mod_vdm_delayed_work(port, x); tcpm_pd_rx_handler(work); tcpm_pd_data_request(port, msg); tcpm_handle_vdm_request(port, msg->payload, cnt); tcpm_queue_vdm(port, response[0], &response[1], rlen - 1); --> WARN_ON(port->vdm_state > VDM_STATE_DONE); For this case, the state machine could still send out discover identity message later if we skip current discover_identity message. So we should handle the received message firstly and override the pending discover_identity message without warning in this case. Then, a delayed send_discover work will send discover_identity message again.
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