Sumit Garg <sumit.garg@xxxxxxxxxx> writes: > On Mon, 6 Apr 2020 at 18:38, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: >> >> On Mon, 2020-04-06 at 16:04 +0300, Kalle Valo wrote: >> > Johannes Berg <johannes@xxxxxxxxxxxxxxxx> writes: >> > >> > > On Mon, 2020-04-06 at 15:52 +0300, Kalle Valo wrote: >> > > > Johannes Berg <johannes@xxxxxxxxxxxxxxxx> writes: >> > > > >> > > > > On Mon, 2020-04-06 at 15:44 +0300, Kalle Valo wrote: >> > > > > > > user-space ieee80211_register_hw() RX IRQ >> > > > > > > +++++++++++++++++++++++++++++++++++++++++++++ >> > > > > > > | | | >> > > > > > > |<---wlan0---wiphy_register() | >> > > > > > > |----start wlan0---->| | >> > > > > > > | |<---IRQ---(RX packet) >> > > > > > > | Kernel crash | >> > > > > > > | due to unallocated | >> > > > > > > | workqueue. | >> > > > > >> > > > > [snip] >> > > > > >> > > > > > I have understood that no frames should be received until mac80211 calls >> > > > > > struct ieee80211_ops::start: >> > > > > > >> > > > > > * @start: Called before the first netdevice attached to the hardware >> > > > > > * is enabled. This should turn on the hardware and must turn on >> > > > > > * frame reception (for possibly enabled monitor interfaces.) >> > > > > >> > > > > True, but I think he's saying that you can actually add and configure an >> > > > > interface as soon as the wiphy is registered? >> > > > >> > > > With '<---IRQ---(RX packet)' I assumed wcn36xx is delivering a frame to >> > > > mac80211 using ieee80211_rx(), but of course I'm just guessing here. >> > > >> > > Yeah, but that could be legitimate? >> > >> > Ah, I misunderstood then. The way I have understood is that no rx frames >> > should be delivered (= calling ieee80211_rx()_ before start() is called, >> > but if that's not the case please ignore me :) >> >> No no, that _is_ the case. But I think the "start wlan0" could end up >> calling it? >> > > Sorry if I wasn't clear enough via the sequence diagram. It's a common > RX packet that arrives via ieee80211_tasklet_handler() which is > enabled via call to "struct ieee80211_ops::start" api. Ah sorry, I didn't realise that. So wcn36xx is not to be blamed then, thanks for the clarification. -- https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
