[Intel-gfx] [PATCH] lockdep: finer-grained completion key for kthread

[Daniel Vetter]

Ideally we'd create the key through a macro at the real callers and
pass it all the way down. This would give us better coverage for cases
where a bunch of kthreads are created for the same thing.
But this gets the job done meanwhile and unblocks our CI. Refining
later on is always possible.

Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 kernel/kthread.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index cd50e99202b0..ef2956516803 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -44,6 +44,10 @@ struct kthread {
 	unsigned long flags;
 	unsigned int cpu;
 	void *data;
+#ifdef CONFIG_LOCKDEP_COMPLETIONS
+	struct lock_class_key parked_key;
+	struct lock_class_key exited_key;
+#endif
 	struct completion parked;
 	struct completion exited;
 #ifdef CONFIG_BLK_CGROUP
@@ -221,8 +225,17 @@ static int kthread(void *_create)
 	}
 
 	self->data = data;
+	/* these two completions are shared with all kthread, which is bonghist
+	 * imo */
+	lockdep_init_map_crosslock(&self->exited->map,
+			"(kthread completion)->exited",
+			&self->exited_key, 0);
 	init_completion(&self->exited);
+	lockdep_init_map_crosslock(&self->parked->map,
+			"(kthread completion)->parked",
+			&self->parked_key, 0);
 	init_completion(&self->parked);
+
 	current->vfork_done = &self->exited;
 
 	/* OK, tell user we're spawned, wait for stop or wakeup */
-- 
2.15.0