This is a note to let you know that I've just added the patch titled
iio: core: fix double free in iio_device_unregister_sysfs()
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 19833c40d0415d6fe4340b5b9c46239abbf718f6 Mon Sep 17 00:00:00 2001
From: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Date: Wed, 13 Oct 2021 11:05:32 +0800
Subject: iio: core: fix double free in iio_device_unregister_sysfs()
I got the double free report:
BUG: KASAN: double-free or invalid-free in kfree+0xce/0x390
iio_device_unregister_sysfs+0x108/0x13b [industrialio]
iio_dev_release+0x9e/0x10e [industrialio]
device_release+0xa5/0x240
If __iio_device_register() fails, iio_dev_opaque->groups will be freed
in error path in iio_device_unregister_sysfs(), then iio_dev_release()
will call iio_device_unregister_sysfs() again, it causes double free.
Set iio_dev_opaque->groups to NULL when it's freed to fix this double free.
Not this is a local work around for a more general mess around life time
management that will get cleaned up and should make this handling
unnecesarry.
Fixes: 32f171724e5c ("iio: core: rework iio device group creation")
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Reviewed-by: Alexandru Ardelean <ardeleanalex@xxxxxxxxx>
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211013030532.956133-1-yangyingliang@xxxxxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
drivers/iio/industrialio-core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 48fda6a79076..3e1e86d987cc 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1600,6 +1600,7 @@ static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
kfree(iio_dev_opaque->chan_attr_group.attrs);
iio_dev_opaque->chan_attr_group.attrs = NULL;
kfree(iio_dev_opaque->groups);
+ iio_dev_opaque->groups = NULL;
}
static void iio_dev_release(struct device *device)
--
2.33.1
