Commit 51a96c77 authored Nov 19, 2010 by Peter Zijlstra Committed by Ingo Molnar Nov 23, 2010

cpu: Remove incorrect BUG_ON



Oleg mentioned that there is no actual guarantee the dying cpu's
migration thread is actually finished running when we get there, so
replace the BUG_ON() with a spinloop waiting for it.

Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 2e01f474

kernel/cpu.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -249,8 +249,11 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
		* The migration_call() CPU_DYING callback will have removed all
		* runnable tasks from the cpu, there's only the idle task left now
		* that the migration thread is done doing the stop_machine thing.
		*
		* Wait for the stop thread to go away.
		*/
		BUG_ON(!idle_cpu(cpu));
		while (!idle_cpu(cpu))
		cpu_relax();

		/* This actually kills the CPU. */
		__cpu_die(cpu);