From: Lars-Peter Clausen <lars@metafoo.de>
To: Jonathan Cameron <jic23@kernel.org>
Cc: Martin Fuzzey <mfuzzey@parkeon.com>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
linux-iio@vger.kernel.org
Subject: Re: [PATCH 1/2] iio: mma8452: Fix trigger reference couting
Date: Thu, 28 Oct 2021 21:52:46 +0200 [thread overview]
Message-ID: <3bf78fdf-c6df-dd77-a1f1-61800c0ebe37@metafoo.de> (raw)
In-Reply-To: <20211028150731.753d4e40@jic23-huawei>
On 10/28/21 4:07 PM, Jonathan Cameron wrote:
> On Sun, 24 Oct 2021 11:26:59 +0200
> Lars-Peter Clausen <lars@metafoo.de> wrote:
>
>> The mma8452 driver directly assigns a trigger to the struct iio_dev. The
>> IIO core when done using this trigger will call `iio_trigger_put()` to drop
>> the reference count by 1.
>>
>> Without the matching `iio_trigger_get()` in the driver the reference count
>> can reach 0 too early, the trigger gets freed while still in use and a
>> use-after-free occurs.
>>
>> Fix this by getting a reference to the trigger before assigning it to the
>> IIO device.
>>
>> Fixes: ae6d9ce05691 ("iio: mma8452: Add support for interrupt driven triggers.")
>> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> Gah. I thought we'd gotten all these years ago. I guess this one slipped through
> the net.
Btw. we already have iio_trigger_set_immutable(), which handles the
reference counting. I was think of adding a iio(_device)_trigger_set()
that does the same except not setting the trig_readonly flag. And then
eventually move the trigger to iio_dev_opaque. Any concerns with this?
next prev parent reply other threads:[~2021-10-28 19:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-24 9:26 [PATCH 1/2] iio: mma8452: Fix trigger reference couting Lars-Peter Clausen
2021-10-24 9:27 ` [PATCH 2/2] iio: trigger: Fix reference counting Lars-Peter Clausen
2021-10-25 10:55 ` Sa, Nuno
2021-10-28 14:16 ` Jonathan Cameron
2021-10-28 16:04 ` Lars-Peter Clausen
2021-10-28 16:12 ` Jonathan Cameron
2021-10-28 14:07 ` [PATCH 1/2] iio: mma8452: Fix trigger reference couting Jonathan Cameron
2021-10-28 19:52 ` Lars-Peter Clausen [this message]
2021-10-30 15:03 ` Jonathan Cameron
2021-10-30 15:12 ` Lars-Peter Clausen
2021-10-30 17:08 ` Jonathan Cameron
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