Messages in this thread Patch in this message | | | Date | Thu, 3 May 2018 14:49:43 +0200 | From | Peter Zijlstra <> | Subject | Re: cpu stopper threads and load balancing leads to deadlock |
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On Thu, May 03, 2018 at 02:40:21PM +0200, Mike Galbraith wrote: > On Thu, 2018-05-03 at 14:28 +0200, Peter Zijlstra wrote: > > > > Hurm.. I don't see how this is 'new'. We moved the wakeup out from under > > stopper lock, but that should not affect the RCU state. > > No, not new, just an additional woes from same spot.
Ah, ok. Does somsething like this make it go away?
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index f89014a2c238..a32518c2ba4a 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -650,8 +650,10 @@ int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data, /* Schedule work on other CPUs and execute directly for local CPU */ set_state(&msdata, MULTI_STOP_PREPARE); cpu_stop_init_done(&done, num_active_cpus()); - queue_stop_cpus_work(cpu_active_mask, multi_cpu_stop, &msdata, - &done); + + RCU_NONIDLE(queue_stop_cpus_work(cpu_active_mask, multi_cpu_stop, + &msdata, &done)); + ret = multi_cpu_stop(&msdata); /* Busy wait for completion. */
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