[PATCH 4.14 27/77] iio: core: Fix entry not deleted when iio_register_sw_trigger_type() fails

Greg Kroah-Hartman
2022-12-05T19:15:20Z

From: Chen Zhongjin <chenzhongjin@huawei.com>

commit 4ad09d956f8eacff61e67e5b13ba8ebec3232f76 upstream.

In iio_register_sw_trigger_type(), configfs_register_default_group() is
possible to fail, but the entry add to iio_trigger_types_list is not
deleted.

This leaves wild in iio_trigger_types_list, which can cause page fault
when module is loading again. So fix this by list_del(&t->list) in error
path.

BUG: unable to handle page fault for address: fffffbfff81d7400
Call Trace:
<TASK>
iio_register_sw_trigger_type
do_one_initcall
do_init_module
load_module
...

Fixes: b662f809d410 ("iio: core: Introduce IIO software triggers")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Link: https://lore.kernel.org/r/20221108032802.168623-1-chenzhongjin@huawei.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/industrialio-sw-trigger.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/iio/industrialio-sw-trigger.c
+++ b/drivers/iio/industrialio-sw-trigger.c
@@ -61,8 +61,12 @@ int iio_register_sw_trigger_type(struct

t->group = configfs_register_default_group(iio_triggers_group, t->name,
&iio_trigger_type_group_type);
- if (IS_ERR(t->group))
+ if (IS_ERR(t->group)) {
+ mutex_lock(&iio_trigger_types_lock);
+ list_del(&t->list);
+ mutex_unlock(&iio_trigger_types_lock);
ret = PTR_ERR(t->group);
+ }

return ret;
}