Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1545375

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

From Mark Greer <mgreer@animalcreek.com>
Newsgroups linux.kernel
Subject Re: [PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel
Date 2016-12-20 20:10 +0100
Message-ID <sQxXs-18O-23@gated-at.bofh.it> (permalink)
References <sQviW-7Qa-41@gated-at.bofh.it> <sQviW-7Qa-39@gated-at.bofh.it>
Organization Animal Creek Technologies, Inc.

Show all headers | View raw


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
--

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH 3/3] nfc: trf7970a: Prevent repeated polling from crashing the kernel Geoff Lansberry <geoff@kuvee.com> - 2016-12-20 17:20 +0100
  Re: [PATCH 3/3] nfc: trf7970a: Prevent repeated polling from  crashing the kernel Mark Greer <mgreer@animalcreek.com> - 2016-12-20 20:10 +0100
    Re: nfc: trf7970a: Prevent repeated polling from crashing the kernel Justin Bronder <justin@kuvee.com> - 2016-12-20 20:20 +0100
      Re: nfc: trf7970a: Prevent repeated polling from crashing the kernel Mark Greer <mgreer@animalcreek.com> - 2016-12-20 21:00 +0100

csiph-web