On Mon, Mar 23, 2020 at 10:21 AM Bobby Jones <rjones@xxxxxxxxxxxxx> wrote: > > Hello net-dev, > > I'm diagnosing a problem with the Toby MPCI-L201 cellular modem where > http operations hang. This is reproducible on the most recent kernel > by turning on the rndis_host driver and executing a wget or similar > http command. I found I was able to still ping but not transfer any > data. After bisecting I've found that commit > a5a18bdf7453d505783e40e47ebb84bfdd35f93b introduces this hang. > > For reference the patch contents are: > > > rndis_host: Set valid random MAC on buggy devices > > > > Some devices of the same type all export the same, random MAC address. This > > behavior has been seen on the ZTE MF910, MF823 and MF831, and there are > > probably more devices out there. Fix this by generating a valid random MAC > > address if we read a random MAC from device. > > > > Also, changed the memcpy() to ether_addr_copy(), as pointed out by > > checkpatch. > > > > Suggested-by: Bjørn Mork <bjorn@xxxxxxx> > > Signed-off-by: Kristian Evensen <kristian.evensen@xxxxxxxxx> > > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> > > diff --git a/drivers/net/usb/rndis_host.c b/drivers/net/usb/rndis_host.c > > index 524a47a28120..4f4f71b2966b 100644 > > --- a/drivers/net/usb/rndis_host.c > > +++ b/drivers/net/usb/rndis_host.c > > @@ -428,7 +428,11 @@ generic_rndis_bind(struct usbnet *dev, struct usb_interface *intf, int flags) > > dev_err(&intf->dev, "rndis get ethaddr, %d\n", retval); > > goto halt_fail_and_release; > > } > > - memcpy(net->dev_addr, bp, ETH_ALEN); > > + > > + if (bp[0] & 0x02) > > + eth_hw_addr_random(net); > > + else > > + ether_addr_copy(net->dev_addr, bp); > > > > /* set a nonzero filter to enable data transfers */ > > memset(u.set, 0, sizeof *u.set); > > I know that there is some internal routing done by the modem firmware, > and I'm assuming that overwriting the MAC address breaks said routing. > Can anyone suggest what a proper fix would be? > > Thanks, > Bobby Adding some individuals and lists in hopes for feedback
