linux-kernel - Re: [PATCH v2] iio: trigger: free trigger resource correctly

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Message-ID: <0b83f5da-1bd8-e6f4-2c58-498d353c6363@kernel.org>
Date:   Sun, 22 Jan 2017 16:15:31 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Lars-Peter Clausen <lars@...afoo.de>,
        Alison Schofield <amsfield22@...il.com>
Cc:     knaack.h@....de, pmeerw@...erw.net, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org, Michael.Hennerich@...log.com,
        gregkh@...uxfoundation.org, devel@...verdev.osuosl.org
Subject: Re: [PATCH v2] iio: trigger: free trigger resource correctly

On 22/01/17 15:56, Lars-Peter Clausen wrote:
> On 01/22/2017 03:25 PM, Jonathan Cameron wrote:
>> On 20/01/17 03:47, Alison Schofield wrote:
>>> These stand-alone trigger drivers were using iio_trigger_put()
>>> where they should have been using iio_trigger_free().  The
>>> iio_trigger_put() adds a module_put which is bad since they
>>> never did a module_get.
>>>
>>> In the sysfs driver, module_get/put's are used as triggers are
>>> added & removed. This extra module_put() occurs on an error path
>>> in the probe routine (probably rare).
>>>
>>> In the bfin-timer & interrupt trigger drivers, the module resources
>>> are not explicitly managed, so it's doing a put on something that
>>> was never get'd.  It occurs on the probe error path and on the
>>> remove path (not so rare).
>>>
>>> Tested with the sysfs trigger driver.
>>> The bfin & interrupt drivers were build tested & inspected only.
>>>
>>> Signed-off-by: Alison Schofield <amsfield22@...il.com>
>> This is certainly more consistent. 
>> Lars, could you sanity check as well given the bfin timer is
>> in here.
> 
> looks good.
> 
Applied to the togreg branch of iio.git.

Thought about sending this as a fix, but as it's been there a long
time I've taken the view there is no real rush on this.

Thanks,

Jonathan