Date: Thu, 24 Nov 2016 12:28:24 +0000
From: Jason Cooper <jason@lakedaemon.net>
To: miaoqing@codeaurora.org
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>,
        linux-wireless@vger.kernel.org,
        Linux ARM Kernel <linux-arm-kernel@lists.infradead.org>,
        ath9k-devel <ath9k-devel@qca.qualcomm.com>,
        ath9k-devel@lists.ath9k.org,
        Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
        Gregory CLEMENT <gregory.clement@free-electrons.com>,
        Kalle Valo <kvalo@codeaurora.org>, Andrew Lunn <andrew@lunn.ch>
Subject: Re: ath9k ARMv7 OOPS in v4.8.6, v4.2.8
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On Thu, Nov 24, 2016 at 02:06:57PM +0800, miaoqing@codeaurora.org wrote:
> 
> >>Okay, so i was 0, so running UP probably isn't going to help.  r7 is
> >>also spec_priv->rfs_chan_spec_scan.
> >>
> >>So, I think the question is... how is this NULL - and has it always
> >>been NULL...
> >
> >The problem appears to be that ath_cmn_process_fft() isn't called that
> >often.  When it is, it crashes in ath_cmn_is_fft_buf_full() because
> >spec_priv->rfs_chan_spec_scan is NULL when ATH9K_DEBUGFS=n. :-(
> >
> >I'm running with ATH9K_DEBUGFS=y now.  If it goes a couple of days
> >without crashing, I'll gin up a patch.
> >
> 
> A similar patch was applied to ath-next branch:
> https://patchwork.kernel.org/patch/9431163/.

Hmm.  Ok, I'm giving it a spin on my board with SMP=y, ATH9K_DEBUGFS=n
(so the only change from known crashing is the patch) and we'll see how
it goes.

Honestly, though, I think the real problem is when kernels are built
without ATH9K_DEBUGFS.  Did the reporter of the crash say if that was
enabled on his system or not?

I'm concerned that there may be other code lurking that secretly depends
on ATH9K_DEBUGFS being enabled.

thx,

Jason.