On Mon, Jun 13, 2016 at 11:08:59AM +0200, Johannes Berg wrote: > On Mon, 2016-06-13 at 07:39 +0200, Michal Kazior wrote: > > > > FWIW all of these are false positives. I think this was already > > pointed out some time ago. The drv_priv stuff is merely an offset > > (see how ieee80211_vif and ieee80211_sta are defined) and the > > according structure is always checked beforehand. OK, fair enough, sorry for the noise. I'm daily running sparse / smatch on wireless-testing; although these had been around for a while they showed up as new "errors" because of some line number changes, but I'll squelch them going forward. > IIRC, doing something like that can (sometimes?) still get you into > undefined behaviour territory, so the compiler could potentially > "optimize" away the later NULL check. So I did just go and check the generated code for each of these cases and gcc didn't elide the subsequent if-test, at least on x86-64 and my compiler / build config. Given http://lwn.net/Articles/342330, it seems possible, though. -- Bob Copeland %% http://bobcopeland.com/ -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
