Messages in this thread | | | Date | Tue, 16 Oct 2018 16:03:22 +0200 | From | Peter Zijlstra <> | Subject | Re: INFO: rcu detected stall in do_idle |
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On Tue, Oct 16, 2018 at 03:24:06PM +0200, Thomas Gleixner wrote: > It does reproduce here but with a kworker stall. Looking at the reproducer: > > *(uint32_t*)0x20000000 = 0; > *(uint32_t*)0x20000004 = 6; > *(uint64_t*)0x20000008 = 0; > *(uint32_t*)0x20000010 = 0; > *(uint32_t*)0x20000014 = 0; > *(uint64_t*)0x20000018 = 0x9917; > *(uint64_t*)0x20000020 = 0xffff; > *(uint64_t*)0x20000028 = 0; > syscall(__NR_sched_setattr, 0, 0x20000000, 0); > > which means: > > struct sched_attr { > .size = 0, > .policy = 6, > .flags = 0, > .nice = 0, > .priority = 0, > .deadline = 0x9917, > .runtime = 0xffff, > .period = 0, > } > > policy 6 is SCHED_DEADLINE > > That makes the thread hog the CPU and prevents all kind of stuff to run. > > Peter, is that expected behaviour?
Sorta, just like FIFO-99 while(1);. Except we should be rejecting the above configuration, because of the rule:
runtime <= deadline <= period
Juri, where were we supposed to check that?
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