From: taehyun cho <taehyun.cho@xxxxxxxxxxx> Endpoint complete function in u_serial can be executed when 'gs_port' is Null. This situation happens when 'dwc3_gadget_pullup' returns ETIMEDOUT. The reason why ETIMEDOUT is returned is that whole system is out of order including interrupt regardless of USB. pc : __lock_acquire+0x54/0x5ec lr : lock_acquire+0xe8/0x198 sp : ffffffc03914b9d0 x29: ffffffc03914b9d0 x28: ffffff895f13b680 x27: 0000000000000000 x26: 0000000000000000 x25: 00000000000003c8 x24: 0000000000000080 x23: ffffffc010a8f650 x22: 0000000000000000 x21: 0000000000000000 x20: 0000000000000000 x19: ffffffc010a8f650 x18: ffffffc02d70a0b0 x17: 0000000000000000 x16: 00000000000229e0 x15: 0000000000000004 x14: 00000000000004f2 x13: ffffffc0120fe178 x12: 0000000000000003 x11: 00000000ffffffff x10: 0000000100000001 x9 : 0000000000000001 x8 : 00000000000003c8 x7 : 0000000000000000 x6 : ffffffc010a8f650 x5 : 0000000000000000 x4 : 0000000000000080 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 00000000000003c8 Call trace: __lock_acquire+0x54/0x5ec lock_acquire+0xe8/0x198 _raw_spin_lock+0x70/0x88 gs_read_complete+0x48/0xac usb_gadget_giveback_request+0x48/0x80 dwc3_gadget_giveback+0xcc/0xe8 dwc3_remove_requests+0xa8/0x188 __dwc3_gadget_ep_disable+0x98/0x110 dwc3_gadget_ep_disable+0x50/0xbc usb_ep_disable+0x44/0x94 gserial_disconnect+0xc0/0x250 acm_free_func+0x30/0x48 usb_put_function+0x34/0x68 config_usb_cfg_unlink+0xdc/0xf8 configfs_unlink+0x144/0x264 vfs_unlink+0x134/0x218 do_unlinkat+0x13c/0x2a0 __arm64_sys_unlinkat+0x48/0x60 el0_svc_common.llvm.10277270529376503802+0xb8/0x1b4 do_el0_svc+0x24/0x8c el0_svc+0x10/0x1c el0_sync_handler+0x68/0xac el0_sync+0x18c/0x1c0 Signed-off-by: taehyun cho <taehyun.cho@xxxxxxxxxxx> --- drivers/usb/gadget/function/u_serial.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index 6f68cbe..af08a18 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -450,6 +450,15 @@ static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) { struct gs_port *port = ep->driver_data; + /* + * Port became NULL when 'dwc3_gadget_pullup' returns ETIMEDOUT. + * Return here to avoid panic. + */ + if (!port) { + pr_err("%s, failed to get port\n", __func__); + return; + } + /* Queue all received data until the tty layer is ready for it. */ spin_lock(&port->port_lock); list_add_tail(&req->list, &port->read_queue); @@ -461,6 +470,15 @@ static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) { struct gs_port *port = ep->driver_data; + /* + * port became NULL when 'dwc3_gadget_pullup' returns ETIMEDOUT. + * Return here to avoid panic. + */ + if (!port) { + pr_err("%s, failed to get port\n", __func__); + return; + } + spin_lock(&port->port_lock); list_add(&req->list, &port->write_pool); port->write_started--; -- 2.7.4