Re: brcmfmac: kernel panic in brcmf_cfg80211_del_key

["Jörg Krause" <jkrause@posteo.de>]

Hi Arend,

On Fr, 2015-01-23 at 15:21 +0100, Arend van Spriel wrote:
> On 01/23/15 13:31, Jörg Krause wrote:
> > Hi all,
> >
> > I'm running an wireless device with Linux kernel 3.18.3 and the brcmfmac
> > driver. When connection the device to my network, I see from time to
> > time these messages in the kernel log:
> >
> > [  899.624759] brcmfmac: brcmf_cfg80211_del_key: invalid key index (4)
> > [  899.649874] brcmfmac: brcmf_cfg80211_del_key: invalid key index (5)
> > [  899.678066] cfg80211: Calling CRDA to update world regulatory domain
> >
> > I'm not sure about the meaning of the 'invalid key index' messages and
> > if it may cause some trouble. However the system is running fine.
> 
> Basically, wpa_supplicant does key deletion for index 0 to 5, but 
> brcmfmac only has 4 keys (0 to 3) hence the message. This is not an issue.

I see!

> 
> > Now I had a test case with two wireless devices having the same hostname
> > and MAC address in the same network.
> 
> What? Why is this a test case. That is fundamentally wrong and asking 
> for trouble.

You're absolutely right! To be honest it's not a real test. We're having
trouble with some wireless audio devices and multiroom playback. In fact
I wanted to simulate in a quick and dirty way what happens if the audio
device does not receive some expected UDP packets from the audio
streaming source because they get lost.

> 
> > The first wireless devices connects to the network and starts receiving
> > an audio stream via UDP. Another device with same hostname and MAC is
> > started after this and repeatedly reboots after 30 seconds.
> >
> > The first device gets disconnected after the second device connects to
> > the network. The device is running with the network tools tools
> > wpa_supplicant, a wpa_action script, udhcpc, avahi, and crda. The device
> > tries to reconnect to the network. It successfully connects, but
> > authentification fails. This step produces a lot of the kernel messages
> > from above.
> >
> > Okay, nothing wrong until here I think. But after some time the brcmfmac
> > driver is dying:
> >
> > [  901.799454] ------------[ cut here ]------------
> > [  901.804332] WARNING: CPU: 0 PID: 104 at
> > drivers/net/wireless/brcm80211/brcmfmac/dhd_linux.c:1076
> > brcmf_netdev_wait_pend8021x+0xe0/0xf4 [brcmfmac]()
> > [  901.866565] Modules linked in:
> > [  901.907705] 	brcmfmac brcmutil
> > [  901.909298] CPU: 0 PID: 104 Comm: wpa_supplicant Not tainted 3.18.3
> > #1
> > [  901.959287] [<c000de40>] (unwind_backtrace) from [<c000c1f4>]
> > (show_stack+0x10/0x14)
> > [  901.993628] [<c000c1f4>] (show_stack) from [<c0016400>]
> > (warn_slowpath_common+0x68/0x88)
> > [  902.016243] [<c0016400>] (warn_slowpath_common) from [<c00164bc>]
> > (warn_slowpath_null+0x1c/0x24)
> > [  902.040249] [<c00164bc>] (warn_slowpath_null) from [<bf016304>]
> > (brcmf_netdev_wait_pend8021x+0xe0/0xf4 [brcmfmac])
> > [  902.067408] [<bf016304>] (brcmf_netdev_wait_pend8021x [brcmfmac])
> > from [<bf0061d8>] (brcmf_cfg80211_get_key+0x1a8/0x374 [brcmfmac])
> > [  902.098434] [<bf0061d8>] (brcmf_cfg80211_get_key [brcmfmac]) from
> > [<bf00770c>] (brcmf_cfg80211_del_key+0x1d8/0x2e0 [brcmfmac])
> > [  902.164527] [<bf00770c>] (brcmf_cfg80211_del_key [brcmfmac]) from
> > [<bf0078ec>] (brcmf_cfg80211_add_key+0xd8/0x248 [brcmfmac])
> > [  902.213096] [<bf0078ec>] (brcmf_cfg80211_add_key [brcmfmac]) from
> > [<c037f368>] (nl80211_new_key+0x108/0x144)
> > [  902.253581] [<c037f368>] (nl80211_new_key) from [<c02ccb98>]
> > (genl_rcv_msg+0x22c/0x39c)
> > [  902.290997] [<c02ccb98>] (genl_rcv_msg) from [<c02cc12c>]
> > (netlink_rcv_skb+0xb4/0xd8)
> > [  902.325813] [<c02cc12c>] (netlink_rcv_skb) from [<c02cc958>]
> > (genl_rcv+0x20/0x34)
> > [  902.363540] [<c02cc958>] (genl_rcv) from [<c02cbaa8>]
> > (netlink_unicast+0x14c/0x1cc)
> > [  902.399402] [<c02cbaa8>] (netlink_unicast) from [<c02cbe98>]
> > (netlink_sendmsg+0x2b8/0x39c)
> > [  902.435798] [<c02cbe98>] (netlink_sendmsg) from [<c0297860>]
> > (sock_sendmsg+0x84/0xa8)
> > [  902.477184] [<c0297860>] (sock_sendmsg) from [<c0298d28>]
> > (___sys_sendmsg.part.32+0x284/0x290)
> > [  902.486197] [<c0298d28>] (___sys_sendmsg.part.32) from [<c0299d34>]
> > (__sys_sendmsg+0x4c/0x7c)
> > [  902.555011] [<c0299d34>] (__sys_sendmsg) from [<c0009620>]
> > (ret_fast_syscall+0x0/0x44)
> > [  902.591178] ---[ end trace 93a9f5360e80c5ca ]---
> >
> > I'm not sure if I should worry about this issue.
> 
> Well, what is happening here is that the driver got a EAPOL message from 
> the network stack to transmit and then got a key config request. That 
> key config is held until transmit of EAPOL is completed. So it is 
> suspicious.

You're right, it's a warning. Does it mean the network stack gets messy
due to this wrong setup?

Best regards
Jörg Krause