[PATCH 4.4 13/56] iio: trigger: free trigger resource correctly

From: Greg Kroah-Hartman
Date: Mon Nov 13 2017 - 08:39:24 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alison Schofield <amsfield22@xxxxxxxxx>


[ 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@xxxxxxxxx>
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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(-)

--- 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(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;
}
--- 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 i
return 0;

out2:
- iio_trigger_put(t->trig);
+ iio_trigger_free(t->trig);
free_t:
kfree(t);
out1:
--- a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
+++ b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
@@ -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;
}