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Subject[PATCH] media input infrastructure:tw686x: Fix of possibleinconsistent memory deallocation and/or race condition by implementation of custom video_device_release function in tw686x driver

Possible inconsistent memory deallocation and/or race conditions were
detected specifically with respect to remaining open handles to the video
device handled by the tw686x driver. This patch addresses this by
implementing a revised independent instance of the video_device_release
function to free the remaining resources and memory where the last open
handle(s) is/were closed.

Signed-off-by: Mark Balantzyan <mbalant3@gmail.com>

---

drivers/media/pci/tw686x/tw686x-video.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/media/pci/tw686x/tw686x-video.c
b/drivers/media/pci/tw686x/tw686x-video.c
index 3a06c000..29e10c85 100644
--- a/drivers/media/pci/tw686x/tw686x-video.c
+++ b/drivers/media/pci/tw686x/tw686x-video.c
@@ -1151,18 +1151,25 @@ void tw686x_video_irq(struct tw686x_dev *dev,
unsigned long requests,
}
}

+void video_device_release(tw686x_dev *dev) {
+ for (int pb = 0; pb < 2; pb++) {
+ dev->dma_ops->free(dev->video_channels,pb);
+ }
+ kfree(dev);
+}
+
void tw686x_video_free(struct tw686x_dev *dev)
{
- unsigned int ch, pb;
+ unsigned int ch;

for (ch = 0; ch < max_channels(dev); ch++) {
struct tw686x_video_channel *vc =
&dev->video_channels[ch];

video_unregister_device(vc->device);

- if (dev->dma_ops->free)
- for (pb = 0; pb < 2; pb++)
- dev->dma_ops->free(vc, pb);
+ if (dev->dma_ops->free) {
+ video_device_release(dev);
+ }
}
}

--
2.17.1
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