[PATCH] binder: fix log spam for existing debugfs file creation.

[Greg Kroah-Hartman]

On Fri, Jan 10, 2020 at 04:44:01PM +0100, Martin Fuzzey wrote:
> Since commit 43e23b6c0b01 ("debugfs: log errors when something goes wrong")
> debugfs logs attempts to create existing files.
> 
> However binder attempts to create multiple debugfs files with
> the same name when a single PID has multiple contexts, this leads
> to log spamming during an Android boot (17 such messages during
> boot on my system).
> 
> Fix this by checking if we already know the PID and only create
> the debugfs entry for the first context per PID.
> 
> Do the same thing for binderfs for symmetry.
> 
> Signed-off-by: Martin Fuzzey <martin.fuzzey at flowbird.group>

Does this need a "Fixes:" and cc: stable tag?

And it would be good to get a review from the binder maintainer(s) to
see if this is sane or not...

thanks,

greg k-h