* [PATCH] iio: core: Fix double free.
@ 2014-07-21 13:22 Martin Fuzzey
2014-07-27 16:42 ` Jonathan Cameron
0 siblings, 1 reply; 2+ messages in thread
From: Martin Fuzzey @ 2014-07-21 13:22 UTC (permalink / raw)
To: linux-iio, Jonathan Cameron
When an error occured 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>
---
drivers/iio/industrialio-core.c | 5 +++--
drivers/iio/industrialio-event.c | 1 +
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 4b1f375..fa06197 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -828,8 +828,7 @@ 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)
{
@@ -837,6 +836,7 @@ 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);
}
}
@@ -917,6 +917,7 @@ 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 bfbf4d4..ad7a35f 100644
--- a/drivers/iio/industrialio-event.c
+++ b/drivers/iio/industrialio-event.c
@@ -492,6 +492,7 @@ 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;
}
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] iio: core: Fix double free.
2014-07-21 13:22 [PATCH] iio: core: Fix double free Martin Fuzzey
@ 2014-07-27 16:42 ` Jonathan Cameron
0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Cameron @ 2014-07-27 16:42 UTC (permalink / raw)
To: Martin Fuzzey, linux-iio
On 21/07/14 14:22, Martin Fuzzey wrote:
> When an error occured 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>
Good catch.
Applied to the fixes-togreg branch of iio.git and marked
for stable.
Given the timing this might end up waiting until after the upcoming merge
windows closes. It's been there a long time with you being the first to notice
so I'm not that fussed about rushing it out and annoying Linus!
Jonathan
> ---
> drivers/iio/industrialio-core.c | 5 +++--
> drivers/iio/industrialio-event.c | 1 +
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 4b1f375..fa06197 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -828,8 +828,7 @@ 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)
> {
> @@ -837,6 +836,7 @@ 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);
> }
> }
> @@ -917,6 +917,7 @@ 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 bfbf4d4..ad7a35f 100644
> --- a/drivers/iio/industrialio-event.c
> +++ b/drivers/iio/industrialio-event.c
> @@ -492,6 +492,7 @@ 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;
> }
>
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2014-07-27 16:42 ` Jonathan Cameron
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