On Thursday 05 March 2015 16:37:12 Johannes Berg wrote: > From: Johannes Berg <johannes.berg@xxxxxxxxx> > > Both minstrel (reported by Sven Eckelmann) and the iwlwifi rate > control aren't properly taking concurrency into account. It's > likely that the same is true for other rate control algorithms. > > In the case of minstrel this manifests itself in crashes when an > update and other data access are run concurrently, for example > when the stations change bandwidth or similar. In iwlwifi, this > can cause firmware crashes. > > Since fixing all rate control algorithms will be very difficult, > just provide locking for invocations. This protects the internal > data structures the algorithms maintain. > > I've manipulated hostapd to test this, by having it change its > advertised bandwidth roughly ever 150ms. At the same time, I'm > running a flood ping between the client and the AP, which causes > this race of update vs. get_rate/status to easily happen on the > client. With this change, the system survives this test. > > Reported-by: Sven Eckelmann <sven@xxxxxxxxxxxxx> > Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Thanks a lot for the patch. This is mostly what I had in mind when asking for the correct lock. I will ask if it is possible to test this patch in an affected network. But I am quite sure that this will not be possible before next week. And your test already sounds quite nice. Kind regards, Sven -- 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
