Messages in this thread | | | Date | Thu, 15 Oct 2020 16:19:57 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 10/19] sched: Fix migrate_disable() vs set_cpus_allowed_ptr() |
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On Thu, Oct 15, 2020 at 02:54:53PM +0100, Valentin Schneider wrote: > > On 15/10/20 12:05, Peter Zijlstra wrote: > > +static int affine_move_task(struct rq *rq, struct rq_flags *rf, > > + struct task_struct *p, int dest_cpu, unsigned int flags) > > +{ > > + struct set_affinity_pending my_pending = { }, *pending = NULL; > > + struct migration_arg arg = { > > + .task = p, > > + .dest_cpu = dest_cpu, > > + }; > > + bool complete = false; > > + > > + /* Can the task run on the task's current CPU? If so, we're done */ > > + if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) { > > + pending = p->migration_pending; > > + if (pending) { > > + p->migration_pending = NULL; > > + complete = true; > > Deciphering my TLA+ deadlock traces leads me to think this needs > > refcount_inc(&pending->refs); > > because the 'goto do_complete' leads us to an unconditional decrement.
Hurmm. I think you're right. I've updated the patch.
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