Merge tag 'sched-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

fecbe78a · Linus Torvalds <[email protected]> · 2026-09-20 09:37:27 -07:00

Pull scheduler fix from Ingo Molnar:

 - Avoid false positive migration warning for proxy donors
   (Andrea Righi)

* tag 'sched-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Avoid false migration warning for proxy donors

Commit: fecbe78ac0e7bb5cdae232444e649a3103d9a917
Parents: abb91eed · fe3c73d7

Merge commit. Changes below are compared with the first parent: abb91eed.

Changes

1 files changed · +8 −1

File	Status	Add	Del	Content
kernel/sched/core.c	modified	+8	−1	View file

kernel/sched/core.c

View file

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7885ff7..0b846a1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3351,6 +3351,8 @@ void relax_compatible_cpus_allowed_ptr(struct task_struct *p)
 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 {
 	unsigned int state = READ_ONCE(p->__state);
+	bool proxy_migrated = sched_proxy_exec() && p->is_blocked &&
+			      task_cpu(p) != p->wake_cpu;
 
 	/*
 	 * We should never call set_task_cpu() on a blocked task,
@@ -3386,7 +3388,12 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 	 */
 	WARN_ON_ONCE(!cpu_online(new_cpu));
 
-	WARN_ON_ONCE(is_migration_disabled(p));
+	/*
+	 * Proxy execution can move a blocked task's scheduling context to any
+	 * CPU without moving its migration-disabled execution context. The
+	 * wakeup path will return the task to a CPU where it can execute.
+	 */
+	WARN_ON_ONCE(is_migration_disabled(p) && !proxy_migrated);
 
 	trace_sched_migrate_task(p, new_cpu);
 