On Tue, Sep 4, 2012 at 3:49 PM, Bjørn Mork <bjorn@xxxxxxx> wrote: > > That's easy: > > - Take any usbnet device supporting remote wakeup (and of course with a > minidriver supporting it as well), > - enable autosuspend, > - ip link set dev ethX/usbX/wwanX up > > And watch ksoftirqd/X use 100% of one of your CPU cores. > > I'd very much like to hear the details if you are unable to reproduce > the bug using this simple test. I have no such kind of devices, and can't reproduce the problem with a cdc-ether gadget built by one omap3 beagleboard. >> Once usbnet_terminate_urbs and netif_device_attach() are >> completed, who will schedule tasklet to trigger rx_alloc_submit? > > That's a good question. It sure would be nice if that never happened > without waking the device first. But there are just too many call sites > for me to follow: To be honest, your patch is correct, and I am just curious about the reason why tasklet is scheduled after the device is suspended. > > bjorn@nemi:/usr/local/src/git/linux$ grep tasklet_schedule drivers/net/usb/usbnet.c > tasklet_schedule(&dev->bh); > * but tasklet_schedule() doesn't. hope the failure is rare. > tasklet_schedule (&dev->bh); > tasklet_schedule(&dev->bh); > tasklet_schedule(&dev->bh); > tasklet_schedule (&dev->bh); > tasklet_schedule (&dev->bh); > tasklet_schedule (&dev->bh); > tasklet_schedule (&dev->bh); > tasklet_schedule (&dev->bh); > tasklet_schedule (&dev->bh); Could you add some debug info inside the caller to see which one cause the tasklet to be scheduled? Thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
