Patch "iio: trigger: free trigger resource correctly" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

iio: trigger: free trigger resource correctly

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
iio-trigger-free-trigger-resource-correctly.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Alison Schofield <[email protected]>
Date: Thu, 19 Jan 2017 19:47:38 -0800
Subject: iio: trigger: free trigger resource correctly

From: Alison Schofield <[email protected]>

[ 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.

---
 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(-)

@@ -58,7 +58,7 @@ static int iio_interrupt_trigger_probe(s
 	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(
 	iio_trigger_unregister(trig);
 	free_irq(trig_info->irq, trig);
 	kfree(trig_info);
-	iio_trigger_put(trig);
+	iio_trigger_free(trig);
 
 	return 0;
 }

@@ -174,7 +174,7 @@ static int iio_sysfs_trigger_probe(int i
 	return 0;
 
 out2:
-	iio_trigger_put(t->trig);
+	iio_trigger_free(t->trig);
 free_t:
 	kfree(t);
 out1:

@@ -259,7 +259,7 @@ out_free_irq:
 out1:
 	iio_trigger_unregister(st->trig);
 out:
-	iio_trigger_put(st->trig);
+	iio_trigger_free(st->trig);
 	return ret;
 }
 

@@ -272,7 +272,7 @@ static int iio_bfin_tmr_trigger_remove(s
 		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;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/iio-trigger-free-trigger-resource-correctly.patch