On 01.12.2023 21:12, Andrew Cooper wrote: > On 01/12/2023 7:59 pm, René Winther Højgaard wrote: >> If I set smt=off and try to configure cpupools with credit(1) as if >> all cores are available, I get the following crash. >> >> The crash happens when I try to use xl cpupool-add-cpu on the disabled >> HT sibling cores. >> >> Hyper-threading is enabled in the firmware, and only disabled with >> smt=off. > > CC'ing some maintainers. > > I expect this will also explode when a CPU is runtime offlined with > `xen-hptool cpu-offline` and then added to a cpupool. > > Interestingly, the crash is mov (%rdx,%rax,1),%r13, and I think that's > the percpu posion value in %rdx. > > I expect cpupools want to reject parked/offline CPUs.
While the only explicit check there is if ( cpu >= nr_cpu_ids ) goto addcpu_out; I would have expected this if ( !cpumask_subset(cpus, &cpupool_free_cpus) || cpumask_intersects(cpus, &cpupool_locked_cpus) ) goto addcpu_out; to deal with the situation, as parked/offline CPUs shouldn't be "free". Jürgen? Jan