From: Martin Fuzzey Date: Thu, 19 Feb 2015 14:17:44 +0000 (+0100) Subject: iio: core: Fix double free. X-Git-Tag: v3.19.5~44 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a8173cd017a912dd333f68bf1c0c31afaf70d4e3;p=thirdparty%2Fkernel%2Fstable.git iio: core: Fix double free. 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 Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index af3e76d652ba0..f009d053384a7 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -832,8 +832,7 @@ static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev, * @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 list_head *attr_list) 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(struct iio_dev *indio_dev) 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) diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c index 0c1e37e3120a4..35c02aeec75e3 100644 --- a/drivers/iio/industrialio-event.c +++ b/drivers/iio/industrialio-event.c @@ -493,6 +493,7 @@ int iio_device_register_eventset(struct iio_dev *indio_dev) 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; }