On Mon, 9 Jan 2012, Sebastian Andrzej Siewior wrote: > On 01/09/2012 04:50 PM, Alan Stern wrote: > > On Mon, 9 Jan 2012, Sebastian Andrzej Siewior wrote: > > > >> This patch adds sg support to dummy_hcd. It seems that uas is not able > >> to work with a hcd which does not support sg only based transfers. > > > > Sometimes it helps to take a second look at things... > > > >> + BUG_ON(!sg_miter_next(miter)); > > ... > >> + BUG_ON(!sg_miter_next(miter)); > > > > BUG_ON is often a very bad idea. It will hang the system if it ever > > triggers in interrupt context. Basically, BUG_ON should be used only > > in situations where things are messed up so badly that crashing is > > better than continuing execution. > > This should not happen at all. It happened during testing while I > forgot to advance the counter. If it happens again during testing, I'm > fine with it because helps catching bugs early. > You want them out? I actually have no idea how to recover except to > give up the transfer. WARN_ON would be okay, and fail the transfer. Or just remove the tests entirely; that wouldn't be any worse than having them fire. As you say, they should never happen. Alan Stern -- 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
