diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2008-11-25 09:59:20 +1030 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-11-26 07:58:29 +0100 |
| commit | 1224e376f2a7e3c7ab19ef37099a78597978a696 (patch) | |
| tree | 244bbf8c345ac70487ddcb6283c7895f6cbdb7dd | |
| parent | 3d8cbdf8650f44d95333ca645d950832a0653f35 (diff) | |
sched: avoid stack var in move_task_off_dead_cpu, fix
Impact: locking fix
We can't call cpuset_cpus_allowed_locked() with the rq lock held.
However, the rq lock merely protects us from (1) cpu_online_mask changing
and (2) someone else changing p->cpus_allowed.
The first can't happen because we're being called from a cpu hotplug
notifier. The second doesn't really matter: we are forcing the task off
a CPU it was affine to, so we're not doing very well anyway.
So we remove the rq lock from this path, and all is good.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 1aa840a9f58..3f5bfdc3d94 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6126,8 +6126,6 @@ static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) */ static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) { - unsigned long flags; - struct rq *rq; int dest_cpu; /* FIXME: Use cpumask_of_node here. */ cpumask_t _nodemask = node_to_cpumask(cpu_to_node(dead_cpu)); @@ -6146,10 +6144,8 @@ again: /* No more Mr. Nice Guy. */ if (dest_cpu >= nr_cpu_ids) { - rq = task_rq_lock(p, &flags); cpuset_cpus_allowed_locked(p, &p->cpus_allowed); dest_cpu = cpumask_any_and(cpu_online_mask, &p->cpus_allowed); - task_rq_unlock(rq, &flags); /* * Don't tell them about moving exiting tasks or |