On 03/20/2013 04:08 PM, Johannes Berg wrote: > >> I am testing the P2P device support patches. Upon stopping the >> wpa_supplicant I get the following warning and when I unload brcmfmac it >> hangs resulting in hung_task_timeout message. The whole rcu stuff still >> needs to settle in my brain. I suspect the warning is related to >> brcmfmac unload failure, but maybe you have some ideas where I should look. > > Hmm, why would stopping the supplicant cause brcmfmac to unload?? Or are > you saying you first stop the supplicant, which gets you that warning, > and then unload fails? Indeed, upon stopping wpa_supplicant I get the warning. And doing a rmmod from the command line after that fails in the hang. >> [ 1634.039095] WARNING: at kernel/rcutree.c:1960 >> rcu_process_callbacks+0x469/0x560() > >> [ 1634.133917] Call Trace: >> [ 1634.139833] [<c1039c92>] warn_slowpath_common+0x72/0xa0 >> [ 1634.148659] [<c10c61f9>] ? rcu_process_callbacks+0x469/0x560 >> [ 1634.157914] [<c10c61f9>] ? rcu_process_callbacks+0x469/0x560 >> [ 1634.167121] [<c1039ce2>] warn_slowpath_null+0x22/0x30 >> [ 1634.175725] [<c10c61f9>] rcu_process_callbacks+0x469/0x560 > > Can't say I understand this warning ... > At least we are on the same page then ;-) >> [ 3606.381631] INFO: task khubd:30 blocked for more than 120 seconds. >> [ 3606.388366] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" >> disables this message. >> [ 3606.396931] khubd D f4f01cd8 0 30 2 0x00000000 >> [ 3606.403609] f4f01d10 00000092 00000000 f4f01cd8 00000246 c1748000 >> c183fb40 c183fb40 >> [ 3606.411731] d46b6273 0000031c f53e7b40 f4d323c0 c1748000 00000246 >> 00000000 f0820090 >> [ 3606.419807] 00000246 f4f01cd8 00000046 00000001 00000046 00000000 >> 00000002 f0820090 >> [ 3606.427881] Call Trace: >> [ 3606.430518] [<c1097aeb>] ? trace_hardirqs_on+0xb/0x10 >> [ 3606.435907] [<c1525ff3>] schedule+0x23/0x60 >> [ 3606.440402] [<f8230c65>] wiphy_unregister+0xa5/0x2e0 [cfg80211] > > This seems to be because you don't remove the p2p device if it's still > present when you unload the driver. Call cfg80211_unregister_wdev() at > some appropriate place. The p2p device is already removed upon stopping wpa_supplicant through .del_virtual_intf() callback. Took a quick peek in net/mac80211/iface.c:ieee80211_if_remove() and wonder whether I should do cfg80211_unregister_wdev() in that code path as well. Guess so, right? Gr. AvS -- 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
