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