Correctly unbind CFE - #7624
Correctly unbind CFE#7624
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cfe_register_node() initialises the node vb2 queue but cfe_unregister_nodes() never released it, causing a memory leak. Release the queue after unregistering the video device so that the driver can be removed, and nodes can later be re-registered without leaking memory. Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
After a node is unregistered its embedded video_device still carries the released struct device and kobject state. Re-registering it triggered a "tried to init an initialized object" and use-after-free situation. Reset the video_device before registering it so that the node can be re-registered after the source subdev is rebound. Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Rebinding or reloading the source sensor driver caused the notifier .complete() callback to run a second time and register duplicate video device entities and links on the media device. This would hit a BUG in media_gobj_create(). Add an .unbind() callback that unregisters the video nodes, removes the CSI2 and FE links and clears the source pointer, so that the graph is rebuilt from scratch on the next .complete(). Tested on Pi 5 with an IMX219 using: echo 11-0010 | sudo tee /sys/bus/i2c/drivers/imx219/unbind echo 11-0010 | sudo tee /sys/bus/i2c/drivers/imx219/bind echo 11-0010 | sudo tee /sys/bus/i2c/drivers/imx219/unbind sudo rmmod imx219 sudo modprobe imx219 Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
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It looks like this applies to the downstream Unicam driver too. (I've never really played with unbinding drivers like that) |
s/downstream/upstream? The unbinding/rebinding is something we might possibly use during production test. |
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Not tested, but looks sane.
It seems odd that so few media platform drivers use the unbind hook as it does appear to be necessary in order to cleanup.
Unloading CFE first and then the sensor driver should generally be clean, and that's what I tend to be doing.
The mainline CFE driver also doesn't have an unbind hook.
I'd looked at downstream, but both downstream and upstream driver for both CFE and Unicam seem to have this omission. |
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Yeah, it's not really something users would normally do day-to-day. |
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I will post this for the upstream driver as well. |
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(Confirmed that the downstream Unicam driver also blows up if you try unbind and rebind, but that is independent of this PR) |
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