| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.19 058/101] iio: core: Fix double free. | Date | Fri, 17 Apr 2015 15:28:46 +0200 |
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3.19-stable review patch. If anyone has any objections, please let me know.
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From: Martin Fuzzey <mfuzzey@parkeon.com>
commit c1b03ab5e886760bdd38c9c7a27af149046ffe01 upstream.
When an error occurred during event registration memory was freed twice resulting in kernel memory corruption and a crash in unrelated code.
The problem was caused by iio_device_unregister_eventset() iio_device_unregister_sysfs()
being called twice, once on the error path and then again via iio_dev_release().
Fix this by making these two functions idempotent so they may be called multiple times.
The problem was observed before applying 78b33216 iio:core: Handle error when mask type is not separate
Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/iio/industrialio-core.c | 5 +++-- drivers/iio/industrialio-event.c | 1 + 2 files changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -832,8 +832,7 @@ static int iio_device_add_channel_sysfs( * @attr_list: List of IIO device attributes * * This function frees the memory allocated for each of the IIO device - * attributes in the list. Note: if you want to reuse the list after calling - * this function you have to reinitialize it using INIT_LIST_HEAD(). + * attributes in the list. */ void iio_free_chan_devattr_list(struct list_head *attr_list) { @@ -841,6 +840,7 @@ void iio_free_chan_devattr_list(struct l list_for_each_entry_safe(p, n, attr_list, l) { kfree(p->dev_attr.attr.name); + list_del(&p->l); kfree(p); } } @@ -921,6 +921,7 @@ static void iio_device_unregister_sysfs( iio_free_chan_devattr_list(&indio_dev->channel_attr_list); kfree(indio_dev->chan_attr_group.attrs); + indio_dev->chan_attr_group.attrs = NULL; } static void iio_dev_release(struct device *device) --- a/drivers/iio/industrialio-event.c +++ b/drivers/iio/industrialio-event.c @@ -493,6 +493,7 @@ int iio_device_register_eventset(struct error_free_setup_event_lines: iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); kfree(indio_dev->event_interface); + indio_dev->event_interface = NULL; return ret; }
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