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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-11-19 20:37:53 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-11-23 10:29:08 +0100 |
| commit | 51a96c77815e7f139892a6e9c8275a50e9baebdf (patch) | |
| tree | 64388fce480b43d0588d108da9e4c526421486cf /kernel/cpu.c | |
| parent | 2e01f4740a874b6085da6ebf541e7ffde9a72bf2 (diff) | |
| download | lwn-51a96c77815e7f139892a6e9c8275a50e9baebdf.tar.gz lwn-51a96c77815e7f139892a6e9c8275a50e9baebdf.zip | |
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>
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 3945066fc01d..cb7a1efa9c2b 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -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); |