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From: Mark Greer <mgreer@animalcreek.com>
To: Geoff Lansberry <geoff@kuvee.com>
Cc: linux-wireless@vger.kernel.org, lauro.venancio@openbossa.org,
	aloisio.almeida@openbossa.org, sameo@linux.intel.com,
	robh+dt@kernel.org, mark.rutland@arm.com, netdev@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	justin@kuvee.com, Jaret Cantu <jaret.cantu@timesys.com>
Subject: Re: [PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel
Date: Tue, 20 Dec 2016 11:59:05 -0700	[thread overview]
Message-ID: <20161220185905.GA5867@animalcreek.com> (raw)
In-Reply-To: <1482250592-4268-3-git-send-email-glansberry@gmail.com>

On Tue, Dec 20, 2016 at 11:16:32AM -0500, Geoff Lansberry wrote:
> From: Jaret Cantu <jaret.cantu@timesys.com>
> 
> 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
--

  reply	other threads:[~2016-12-20 19:00 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-20 16:16 [PATCH 1/3] NFC: trf7970a: add device tree option for 27MHz clock Geoff Lansberry
2016-12-20 16:16 ` [PATCH 2/3] NFC: trf7970a: Add device tree option of 1.8 Volt IO voltage Geoff Lansberry
2016-12-21  2:23   ` Mark Greer
2016-12-21 11:47     ` Geoff Lansberry
2016-12-21 16:13       ` Mark Greer
2016-12-20 16:16 ` [PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Geoff Lansberry
2016-12-20 18:59   ` Mark Greer [this message]
2016-12-20 19:13     ` Justin Bronder
2016-12-20 19:56       ` Mark Greer
2016-12-20 17:58 ` [PATCH 1/3] NFC: trf7970a: add device tree option for 27MHz clock Jones Desougi
2016-12-20 18:11 ` Mark Greer
2016-12-20 18:29   ` Geoff Lansberry
2016-12-20 18:35     ` Mark Greer
  -- strict thread matches above, loose matches on Subject: below --
2016-12-20 16:10 Geoff Lansberry
2016-12-20 16:10 ` [PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Geoff Lansberry
2016-12-15 22:30 [PATCH 1/3] NFC: trf7970a: add device tree option for 27MHz clock Geoff Lansberry
2016-12-15 22:30 ` [PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Geoff Lansberry
2016-12-16  1:18   ` Mark Greer

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