linux-kernel - [PATCH AUTOSEL for 4.9 21/50] iio: trigger: free trigger resource correctly

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Date:   Wed, 25 Oct 2017 01:55:57 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Alison Schofield <amsfield22@...il.com>,
        Jonathan Cameron <jic23@...nel.org>,
        "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
Subject: [PATCH AUTOSEL for 4.9 21/50] iio: trigger: free trigger resource
 correctly

From: Alison Schofield <amsfield22@...il.com>

[ Upstream commit 10e840dfb0b7fc345082dd9e5fff3c1c02e7690e ]

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>
Signed-off-by: Jonathan Cameron <jic23@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 drivers/iio/trigger/iio-trig-interrupt.c          | 8 ++++----
 drivers/iio/trigger/iio-trig-sysfs.c              | 2 +-
 drivers/staging/iio/trigger/iio-trig-bfin-timer.c | 4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/trigger/iio-trig-interrupt.c b/drivers/iio/trigger/iio-trig-interrupt.c
index 572bc6f02ca8..e18f12b74610 100644
--- a/drivers/iio/trigger/iio-trig-interrupt.c
+++ b/drivers/iio/trigger/iio-trig-interrupt.c
@@ -58,7 +58,7 @@ static int iio_interrupt_trigger_probe(struct platform_device *pdev)
 	trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
 	if (!trig_info) {
 		ret = -ENOMEM;
-		goto error_put_trigger;
+		goto error_free_trigger;
 	}
 	iio_trigger_set_drvdata(trig, trig_info);
 	trig_info->irq = irq;
@@ -83,8 +83,8 @@ error_release_irq:
 	free_irq(irq, trig);
 error_free_trig_info:
 	kfree(trig_info);
-error_put_trigger:
-	iio_trigger_put(trig);
+error_free_trigger:
+	iio_trigger_free(trig);
 error_ret:
 	return ret;
 }
@@ -99,7 +99,7 @@ static int iio_interrupt_trigger_remove(struct platform_device *pdev)
 	iio_trigger_unregister(trig);
 	free_irq(trig_info->irq, trig);
 	kfree(trig_info);
-	iio_trigger_put(trig);
+	iio_trigger_free(trig);
 
 	return 0;
 }
diff --git a/drivers/iio/trigger/iio-trig-sysfs.c b/drivers/iio/trigger/iio-trig-sysfs.c
index 3dfab2bc6d69..202e8b89caf2 100644
--- a/drivers/iio/trigger/iio-trig-sysfs.c
+++ b/drivers/iio/trigger/iio-trig-sysfs.c
@@ -174,7 +174,7 @@ static int iio_sysfs_trigger_probe(int id)
 	return 0;
 
 out2:
-	iio_trigger_put(t->trig);
+	iio_trigger_free(t->trig);
 free_t:
 	kfree(t);
 out1:
diff --git a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
index 38dca69a06eb..ce500a509aa2 100644
--- a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
+++ b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
@@ -260,7 +260,7 @@ out_free_irq:
 out1:
 	iio_trigger_unregister(st->trig);
 out:
-	iio_trigger_put(st->trig);
+	iio_trigger_free(st->trig);
 	return ret;
 }
 
@@ -273,7 +273,7 @@ static int iio_bfin_tmr_trigger_remove(struct platform_device *pdev)
 		peripheral_free(st->t->pin);
 	free_irq(st->irq, st);
 	iio_trigger_unregister(st->trig);
-	iio_trigger_put(st->trig);
+	iio_trigger_free(st->trig);
 
 	return 0;
 }
-- 
2.11.0