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| author | Oleg Nesterov <oleg@redhat.com> | 2010-03-15 10:10:23 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-04-02 20:12:03 +0200 |
| commit | 6a1bdc1b577ebcb65f6603c57f8347309bc4ab13 (patch) | |
| tree | 516130eedf782dd14505bd111e06bcfad9923b07 /kernel/sched.c | |
| parent | 30da688ef6b76e01969b00608202fff1eed2accc (diff) | |
| download | lwn-6a1bdc1b577ebcb65f6603c57f8347309bc4ab13.tar.gz lwn-6a1bdc1b577ebcb65f6603c57f8347309bc4ab13.zip | |
sched: _cpu_down(): Don't play with current->cpus_allowed
_cpu_down() changes the current task's affinity and then recovers it at
the end. The problems are well known: we can't restore old_allowed if it
was bound to the now-dead-cpu, and we can race with the userspace which
can change cpu-affinity during unplug.
_cpu_down() should not play with current->cpus_allowed at all. Instead,
take_cpu_down() can migrate the caller of _cpu_down() after __cpu_disable()
removes the dying cpu from cpu_online_mask.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100315091023.GA9148@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 165b532dd8c2..11119deffa48 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5442,7 +5442,7 @@ static int migration_thread(void *data) /* * Figure out where task on dead CPU should go, use force if necessary. */ -static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) +void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) { struct rq *rq = cpu_rq(dead_cpu); int needs_cpu, uninitialized_var(dest_cpu); |