Kernel panic hosting 5Ghz AP

[Kalle Valo]

Konstantin Bogomolov <konstantin.bogomolov at dejero.com> writes:

> I have an issue where I get a kernel panic upon hosting the following
> AP with hostapd version 2.4 :
>
> # cat hostapd1.conf
> interface=hotspot0
> driver=nl80211
> hw_mode=a
> channel=0
> ieee80211d=1
> country_code=CA
> ieee80211ac=1
> ssid=test5
> auth_algs=1
> wpa=2
> wpa_key_mgmt=WPA-PSK
> rsn_pairwise=CCMP
> wpa_passphrase=testtest
>
> I am using a stock Debian Stretch 4.9 kernel, with the latest ath10k
> firmware. The card I am using is:
>
> 02:00.0 Network controller: Qualcomm Atheros QCA6174 802.11ac Wireless
> Network Adapter (rev 32)
>     Subsystem: AzureWave QCA6174 802.11ac Wireless Network Adapter
>     Flags: bus master, fast devsel, latency 0, IRQ 326
>     Memory at df000000 (64-bit, non-prefetchable) [size=2M]
>     Capabilities: [40] Power Management version 3
>     Capabilities: [50] MSI: Enable+ Count=1/8 Maskable+ 64bit-
>     Capabilities: [70] Express Endpoint, MSI 00
>     Capabilities: [100] Advanced Error Reporting
>     Capabilities: [148] Virtual Channel
>     Capabilities: [168] Device Serial Number 00-00-00-00-00-00-00-00
>     Capabilities: [178] Latency Tolerance Reporting
>     Capabilities: [180] L1 PM Substates
>     Kernel driver in use: ath10k_pci
>     Kernel modules: ath10k_pci
>
>
> I get the following dmesg logs from the panic:
>
> [   84.211731] IPv6: ADDRCONF(NETDEV_UP): hotspot0: link is not ready
> [   84.212359] BUG: unable to handle kernel NULL pointer dereference
> at 0000000000000020
> [   84.212410] IP: [<ffffffffaa8ed9ed>] skb_release_data+0x8d/0x110

Did you see this once or multiple times? Are you able to reproduce the
crash? Is this a regression (in other words did it work ok before)? At
what stage exactly does it crash, do you need to do something special to
make it crash?

Trying out a recent vanilla kernel.org release would be helpful to
pinpoint the problem as the Debian kernel might have custom patches
causing problems.

-- 
Kalle Valo