Messages in this thread | | | Date | Tue, 11 Dec 2018 19:50:59 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH V2] x86/intel_rdt: Ensure usage of CPUs are locked while needed |
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On Tue, Dec 11, 2018 at 10:33:59AM -0800, Reinette Chatre wrote: > I am not sure that this is an issue when updating a schemata in the > general case. In the case when just CAT schemata (without > pseudo-locking) is updated then the cpu mask associated with the cache > instance is indeed used to determine which CPUs should have their > registers changed but only the current CPU is not checked for being > online, for the other CPUs smp_call_function_many() is used that > includes an online check.
Well, in your fix rdtgroup_schemata_write() disables hotplug for its whole duration and doesn't look at what schemata update is being done, right?
> I had the same question in V1's notes to the maintainer :)
Whoops, and I read that... Sorry. :-\
> My initial concern was the lack of IS_ERR checking. Understanding the > flow better now it seems to me that this is indeed not a bug now. The > reasoning is that an ERR_PTR is only returned when a negative id is > provided in the parameters to rdt_find_domain(). There are currently > only two places where a negative id could be provided to > rdt_find_domain(), domain_add_cpu() and domain_remove_cpu(), and both > locations test the return value using IS_ERR.
Right. I'll queue it for the normal merge window.
Thx.
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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