Re: [PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel

[Mark Greer]

On Tue, Dec 20, 2016 at 11:16:32AM -0500, Geoff Lansberry wrote:
> From: Jaret Cantu <jaret.cantu@xxxxxxxxxxx>
> 
> Repeated polling attempts cause a NULL dereference error to occur.
> This is because the state of the trf7970a is currently reading but
> another request has been made to send a command before it has finished.

How is this happening?  Was trf7970a_abort_cmd() called and it didn't
work right?  Was it not called at all and there is a bug in the digital
layer?  More details please.

> The solution is to properly kill the waiting reading (workqueue)
> before failing on the send.

If the bug is in the calling code, then that is what should get fixed.
This seems to be a hack to work-around a digital layer bug.

Mark
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