From c0d848fcb09d80a5f48b99f85e448185125ef59f Mon Sep 17 00:00:00 2001 From: James Morse Date: Wed, 21 Feb 2024 12:23:06 +0000 Subject: [PATCH] x86/resctrl: Remove lockdep annotation that triggers false positive 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. [ bp: Refresh it ontop of x86/cache. ] Fixes: fb700810d30b ("x86/resctrl: Separate arch and fs resctrl locks") Reported-by: Tony Luck Signed-off-by: James Morse Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/all/ZdUSwOM9UUNpw84Y@agluck-desk3 --- 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 8a4ef4f5bddc..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_HOTPLUG_CPU) && IS_ENABLED(CONFIG_LOCKDEP)) - WARN_ON_ONCE(!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))