[PATCH 1/2] media: au0828 fix to protect enable/disable source set and clear

From: Shuah Khan
Date: Mon Nov 28 2016 - 21:15:52 EST


Protect enable/disable source set and clear to avoid races with callers.
There is a possibility clear could occur while dvb-core and v4l2 try to
access these handlers.

Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
---
drivers/media/usb/au0828/au0828-core.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
index bf53553..a1f696a 100644
--- a/drivers/media/usb/au0828/au0828-core.c
+++ b/drivers/media/usb/au0828/au0828-core.c
@@ -153,9 +153,11 @@ static void au0828_unregister_media_device(struct au0828_dev *dev)
}

/* clear enable_source, disable_source */
+ mutex_lock(&mdev->graph_mutex);
dev->media_dev->source_priv = NULL;
dev->media_dev->enable_source = NULL;
dev->media_dev->disable_source = NULL;
+ mutex_unlock(&mdev->graph_mutex);

media_device_unregister(dev->media_dev);
media_device_cleanup(dev->media_dev);
@@ -549,9 +551,11 @@ static int au0828_media_device_register(struct au0828_dev *dev,
return ret;
}
/* set enable_source */
+ mutex_lock(&dev->media_dev->graph_mutex);
dev->media_dev->source_priv = (void *) dev;
dev->media_dev->enable_source = au0828_enable_source;
dev->media_dev->disable_source = au0828_disable_source;
+ mutex_unlock(&dev->media_dev->graph_mutex);
#endif
return 0;
}
--
2.7.4