Re: [v6.1.52][PATCH] Bluetooth: btsdio: fix use after free bug in btsdio_remove due to race condition

[Greg KH]

On Wed, Sep 06, 2023 at 05:45:25PM +0530, Deepak Rathore wrote:
> From: Zheng Wang <zyytlz.wz@xxxxxxx>
> 
> [ Upstream commit 73f7b171b7c09139eb3c6a5677c200dc1be5f318 ]
> 
> In btsdio_probe, the data->work is bound with btsdio_work. It will be
> started in btsdio_send_frame.
> 
> If the btsdio_remove runs with a unfinished work, there may be a race
> condition that hdev is freed but used in btsdio_work. Fix it by
> canceling the work before do cleanup in btsdio_remove.
> 
> Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
> Signed-off-by: Deepak Rathore <deeratho@xxxxxxxxx>

Meta-comment, are you SURE you want this applied?  If so, why was it
reverted upstream in 6.4 in commit db2bf510bd5d ("Revert "Bluetooth:
btsdio: fix use after free bug in btsdio_remove due to unfinished
work"")

What testing did you do that determined this should be added to the
tree?  How did you come up with just this one commit to be requested to
be applied to just this one branch?

thanks,

greg k-h-