Re: [Re] kernel panic during shutdown in v7.1+ with PREEMPT_RT

Bert Karwatzki <[email protected]> Mon, 27 Jul 2026 12:06:55 +0200
Newsgroups dev.linux.lists.linux-rt-devel,org.kernel.vger.linux-kernel,org.kernel.vger.linux-next
Message-ID <[email protected]>
This can be fixed like this

struct dc_plane_state *dc_create_plane_state(const struct dc *dc)
{
	struct dc_plane_state *plane_state;
	DC_RUN_WITH_PREEMPTION_ENABLED(plane_state = kvzalloc_obj(*plane_state, GFP_ATOMIC));

	if (NULL == plane_state)
		return NULL;

	kref_init(&plane_state->refcount);
	dc_plane_construct(dc->ctx, plane_state);

	return plane_state;
}

I also found missing DC_RUN_WITH_PREEMPTION_ENABLED in an error path, I'm preparing
a patch for next-20260721 (next-20260722+ have broken reboot due to the mt7925 issue
mentioned above).
 Also, is preempt_{disable,enable}() really necessary in DC_FPU_{BEGIN,END}?
Could migrate_{disable,enable}() be enough instead? This way we wouldn't need
DC_RUN_WITH_PREEMPTION_ENABLED at all(?).

Bert Karwatzki