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From: Dmitry Rokosov <DDRokosov@sberdevices.ru>
To: "robh+dt@kernel.org" <robh+dt@kernel.org>,
	"jic23@kernel.org" <jic23@kernel.org>,
	"lars@metafoo.de" <lars@metafoo.de>,
	"andy.shevchenko@gmail.com" <andy.shevchenko@gmail.com>,
	"lorenzo.bianconi83@gmail.com" <lorenzo.bianconi83@gmail.com>
Cc: "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
	kernel <kernel@sberdevices.ru>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Dmitry Rokosov <DDRokosov@sberdevices.ru>
Subject: [PATCH v1 5/5] iio:humidity:hts221: rearrange iio trigger get and register
Date: Mon, 23 May 2022 18:36:30 +0000	[thread overview]
Message-ID: <20220523183716.20360-1-ddrokosov@sberdevices.ru> (raw)
In-Reply-To: <20220523164159.11579-1-ddrokosov@sberdevices.ru>

IIO trigger interface function iio_trigger_get() should be called after
iio_trigger_register() (or its devm analogue) strictly, because of
iio_trigger_get() acquires module refcnt based on the trigger->owner
pointer, which is initialized inside iio_trigger_register() to
THIS_MODULE.
If this call order is wrong, the next iio_trigger_put() (from sysfs
callbacks or rmmod) will derefence "default" module refcnt, which is
completely incorrect.

Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
---
 drivers/iio/humidity/hts221_buffer.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/humidity/hts221_buffer.c b/drivers/iio/humidity/hts221_buffer.c
index f29692b9d2db..66b32413cf5e 100644
--- a/drivers/iio/humidity/hts221_buffer.c
+++ b/drivers/iio/humidity/hts221_buffer.c
@@ -135,9 +135,12 @@ int hts221_allocate_trigger(struct iio_dev *iio_dev)
 
 	iio_trigger_set_drvdata(hw->trig, iio_dev);
 	hw->trig->ops = &hts221_trigger_ops;
+
+	err = devm_iio_trigger_register(hw->dev, hw->trig);
+
 	iio_dev->trig = iio_trigger_get(hw->trig);
 
-	return devm_iio_trigger_register(hw->dev, hw->trig);
+	return err;
 }
 
 static int hts221_buffer_preenable(struct iio_dev *iio_dev)
-- 
2.36.0

      parent reply	other threads:[~2022-05-23 18:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-23 16:41 [PATCH v1 0/5] iio: treewide: rearrange iio trig get/register Dmitry Rokosov
2022-05-23 16:41 ` [PATCH v1 1/5] iio:accel:bma180: rearrange iio trigger get and register Dmitry Rokosov
2022-05-23 16:41 ` [PATCH v1 2/5] iio:accel:kxcjk-1013: " Dmitry Rokosov
2022-05-23 16:41 ` [PATCH v1 3/5] iio:accel:mxc4005: " Dmitry Rokosov
2022-05-23 16:41 ` [PATCH v1 4/5] iio:chemical:ccs811: " Dmitry Rokosov
2022-05-23 17:40 ` [PATCH v1 0/5] iio: treewide: rearrange iio trig get/register Andy Shevchenko
2022-05-23 19:06   ` Dmitry Rokosov
2022-05-23 18:36 ` Dmitry Rokosov [this message]

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