media: cxusb: no longer judge rbuf when the write fails
In the Linux kernel, the following vulnerability has been resolved: media: cxusb: no longer judge rbuf when the write fails syzbot reported a uninit-value in cxusb_i2c_xfer. [1] Only when the write operation of usb_bulk_msg() in dvb_usb_generic_rw() succeeds and rlen is greater than 0, the read operation of usb_bulk_msg() will be executed to read rlen bytes of data from the dvb device into the rbuf. In this case, although rlen is 1, the write operation failed which resulted in the dvb read operation not being executed, and ultimately variable i was not initialized. [1] BUG: KMSAN: uninit-value in cxusb_gpio_tuner drivers/media/usb/dvb-us