On 04.12.23 10:15, Jan Beulich wrote:
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?
The problem is the call of sched_get_opt_cpumask() to need the percpu area of the cpu in question. Juergen
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