Re: ath10k/QCA9980 - Issues introduced in wireless testing 2016-05

[Felix Fietkau <nbd@nbd.name>]

On 2016-06-10 10:50, Michal Kazior wrote:
> On 9 June 2016 at 09:46, A. Benz <ash.benz@bk.ru> wrote:
>> Dear All,
>>
>> I am using LEDE on my IPQ806x (QCA9980) system (Archer C2600).
>> With compat-wireless-2016-05-12, I observed traces attached below.
>> The router is unstable and eventually reboots by itself (randomly).
>>
>> Upon reverting to compat-wireless-2016-01, the issue disappears. Nothing
>> else is changed (software-wise or hardware).
>> This was confirmed with other users.
>>
>> A new compile with the fixes below:
>> https://git.lede-project.org/?p=lede/nbd/staging.git;a=commit;h=858e26f3c0fc11231f25497cbb2ddca1e5f101e0
>>
>> Did not solve the problem.
>>
>> Please let me know if I need to provide any further information.
>>
>> ------------[ cut here ]------------
>> WARNING: CPU: 0 PID: 558 at
>> compat-wireless-2016-05-12/net/mac80211/rx.c:4068
>> ieee80211_rx_napi+0x8c/0x8a4 [mac80211]()
> 
> Can you post what is at rx.c line 4068 (and +/- 3 lines), please?
It's early in ieee80211_rx_napi:

    sband = local->hw.wiphy->bands[status->band];
    if (WARN_ON(!sband))
        goto drop;

I could not easily find a scenario under which status->band would not be
set properly by the driver, so my guess is there is some nasty memory
corruption going on.

FWIW, I've received several reports like this from different people on
different devices. They're also confirming that reverting to the
snapshot from January makes things stable again.

- Felix