[ath9k-devel] [PATCH] ath9k: Disable spectral scan code to fix crash on rmmod.

[Ben Greear <greearb@candelatech.com>]

On 05/08/2013 10:37 PM, Sujith Manoharan wrote:
> greearb at candelatech.com wrote:
>> From: Ben Greear <greearb@candelatech.com>
>>
>> With CONFIG_ATH9K_DEBUGFS enabled, and slub memory poisoning
>> enabled, I see this crash on rmmod of ath9k.  I'm not sure how
>> to fix this properly, but in the meantime, this patch to disable
>> the spectral scan code works around the problem for me.
>>
>> With memory poisoning and the verify_mem_not_deleted code
>> below added, the crash looks as follows...  The dentry
>> is not *always* freed at this point, probably because rcu
>> callbacks haven't completed.  You still get a crash soon
>> after, however.
>
> The relay file should probably be closed before calling ieee80211_unregister_hw().
> The ath9k debugfs directory is created inside the phy#/ directory and that would
> get cleaned up when the wiphy is unregistered.
>
> Does this help ?

This fixes the problem for me, and certainly is less of a hack than
what I posted.

I did several module unloads with memory poisoning enabled, system
remains stable.

Tested-by: Ben Greear <greearb@candelatech.com>

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com