[PATCH v12 19/28] coresight: Save active path for system tracers

[Leo Yan]

On Fri, May 15, 2026 at 11:54:22AM +0100, Suzuki K Poulose wrote:

[...]

> > +	/*
> > +	 * Update the path pointer until after the source is enabled to avoid
> > +	 * races where multiple paths attempt to enable the same source.
> > +	 *
> > +	 * Do not set the path pointer here for per-CPU sources; set it locally
> > +	 * on the CPU instead. Otherwise, there is a window where the path is
> > +	 * enabled but the pointer is not yet set, causing CPU PM notifiers to
> > +	 * miss PM operations due to reading a NULL pointer.
> > +	 */
> > +	if (!coresight_is_percpu_source(csdev))
> > +		csdev->path = path;
> 
> Do we need to specail case this for non-percpu sources ? We could always let
> the driver save/clear the path leaving the core out of it. We can fix it
> separately from this series in a follow up patch.

This patch has a big reason is for patch 22. After saving csdev->path,
then patch 22 can totally remove IDR cache related things.

Otherwise, we can drop this patch and patch 22, this wouldn't impact
CPU PM stuffs.

Thanks,
Leo