Messages in this thread | | | Date | Tue, 9 Apr 2024 10:42:13 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/2] x86/cpu/topology: don't write to immutable cpu_present_mask |
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* Thomas Gleixner <tglx@linutronix.de> wrote:
> On Sun, Apr 07 2024 at 18:26, Alexey Dobriyan wrote: > > Workaround the following oops: > > > > topology_hotplug_apic > > topo_set_cpuids > > set_cpu_possible(cpu, true); > > // write to __ro_after_init section after init > > Duh, yes. > > > adobriyan: I'm not sure what's going on, can it set unset bit here? > > If not, then why does it repeat the job and set already set bits. > > > > Anyhow, let's not oops peoples' machines for now. > > Adding a bandaid to paper over the non-understood real problem is > definitely not a good plan. I take this patch as a bug report. > > Proper fix below.
BTW., independently of the fix, warning about a too late set_cpu_possible() might still make sense - clearly it *can* be called too late by architecture init code :-)
It's not a performance-sensitive function in any case, so the extra debugging code might not hurt.
Thanks,
Ingo
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