On Thu, May 20, 2021 at 09:25:53PM +0000, Guido Kiener wrote: > I've tested to pull the cable and I can easy produce the -EPROTO (-71) error in the usbtmc.c driver. > The error also happens when I have no traffic and just switch off the USBTMC device (which I can do from home office). > When there is traffic, the IN/OUT pipe will also show some -EPROTO errors from the flying urbs. > > On my test PC the amount of error messages vary from 1 to ca. 10 error message issued by the INT pipe (see below). > Nevertheless I do not see the endless loop, since the USB disconnect stops the loop. > (Tested with USB 2.0, older kernel 4.15, but latest modified usbtmc.c driver using ehci-pci) > So I can test fixes (of course with latest kernel) and also setup a machine with USB 3.0. > > 1. Example > [1616527.017863] usbtmc 1-1.4:1.0: usbtmc_write_bulk_cb - nonzero write bulk status received: -71 > [1616527.032489] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.053998] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.076145] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.098143] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.120244] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.142244] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.164440] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.186517] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.208175] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.230272] usbtmc 1-1.4:1.0: unknown status received: -71 > [1616527.241982] usb 1-1.4: USB disconnect, device number 3 > > 2. Example > [1622454.299131] usbtmc 1-1.4:1.0: unknown status received: -71 > [1622454.305815] usbtmc 1-1.4:1.0: usbtmc_write_bulk_cb - nonzero write bulk status received: -71 > [1622454.309921] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -71 > [1622454.319121] usbtmc 1-1.4:1.0: unknown status received: -71 > [1622454.341199] usbtmc 1-1.4:1.0: unknown status received: -71 > [1622454.363336] usbtmc 1-1.4:1.0: unknown status received: -71 > [1622454.385466] usbtmc 1-1.4:1.0: unknown status received: -71 > [1622454.407576] usbtmc 1-1.4:1.0: unknown status received: -71 > [1622454.422870] usb 1-1.4: USB disconnect, device number 7 > > 3. Example > [1623429.713784] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -71 > [1623429.714037] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.714279] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.714528] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.714778] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.715029] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.715278] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.715528] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.715777] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.716028] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.716277] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.718916] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.719168] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.722404] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.725666] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.725918] usbtmc 1-1.4:1.0: usbtmc_read_bulk_cb - nonzero read bulk status received: -2 > [1623429.727837] usbtmc 1-1.4:1.0: unknown status received: -71 > [1623429.749949] usbtmc 1-1.4:1.0: unknown status received: -71 > [1623429.772094] usbtmc 1-1.4:1.0: unknown status received: -71 > [1623429.794184] usbtmc 1-1.4:1.0: unknown status received: -71 > [1623429.816297] usbtmc 1-1.4:1.0: unknown status received: -71 > [1623429.838479] usbtmc 1-1.4:1.0: unknown status received: -71 > [1623429.838795] usb 1-1.4: USB disconnect, device number 8 Try running this test on a system with only one CPU (and no hyperthreading). I think that's the environment syzbot emulates. Alan Stern
