Messages in this thread | | | Date | Wed, 21 Feb 2024 08:48:24 -0800 | Subject | Re: [PATCH] x86/resctrl: Remove lockdep annotation that triggers false positive | From | Reinette Chatre <> |
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Hi James,
On 2/21/2024 4:23 AM, James Morse wrote: > get_domain_from_cpu() walks a list of domains to find the one that > contains the specified CPU. This needs to be protected against races > with CPU hotplug when the list is modified. It has recently gained a > lockdep annotation to check this. > > The lockdep annotation causes false positives when called via IPI > as the lock is held, but by another process. Remove it. > > Reported-by: Tony Luck <tony.luck@intel.com> > Link: https://lore.kernel.org/all/ZdUSwOM9UUNpw84Y@agluck-desk3/ > Fixes: fb700810d30b ("x86/resctrl: Separate arch and fs resctrl locks") > Signed-off-by: James Morse <james.morse@arm.com> > --- > arch/x86/kernel/cpu/resctrl/core.c | 9 --------- > 1 file changed, 9 deletions(-) > > diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c > index 9f1aa555a8ea..83e40341583e 100644 > --- a/arch/x86/kernel/cpu/resctrl/core.c > +++ b/arch/x86/kernel/cpu/resctrl/core.c > @@ -362,15 +362,6 @@ struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r) > { > struct rdt_domain *d; > > - /* > - * Walking r->domains, ensure it can't race with cpuhp. > - * Because this is called via IPI by rdt_ctrl_update(), assertions > - * about locks this thread holds will lead to false positives. Check > - * someone is holding the CPUs lock. > - */ > - if (IS_ENABLED(CONFIG_LOCKDEP)) > - lockdep_is_cpus_held(); > - > list_for_each_entry(d, &r->domains, list) { > /* Find the domain that contains this CPU */ > if (cpumask_test_cpu(cpu, &d->cpu_mask))
I agree with this change. Could you please base it on x86/cache branch of tip?
Thank you
Reinette
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