From ee139385432e919f4d1f59b80edbc073cdae1391 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Fri, 25 Sep 2020 06:49:05 -0700 Subject: [PATCH] perf/x86/intel/uncore: Reduce the number of CBOX counters An oops is triggered by the fuzzy test. [ 327.853081] unchecked MSR access error: RDMSR from 0x70c at rIP: 0xffffffffc082c820 (uncore_msr_read_counter+0x10/0x50 [intel_uncore]) [ 327.853083] Call Trace: [ 327.853085] [ 327.853089] uncore_pmu_event_start+0x85/0x170 [intel_uncore] [ 327.853093] uncore_pmu_event_add+0x1a4/0x410 [intel_uncore] [ 327.853097] ? event_sched_in.isra.118+0xca/0x240 There are 2 GP counters for each CBOX, but the current code claims 4 counters. Accessing the invalid registers triggers the oops. Fixes: 6e394376ee89 ("perf/x86/intel/uncore: Add Intel Icelake uncore support") Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200925134905.8839-3-kan.liang@linux.intel.com --- arch/x86/events/intel/uncore_snb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/events/intel/uncore_snb.c b/arch/x86/events/intel/uncore_snb.c index 2bdfcf80b434..de3d9621b694 100644 --- a/arch/x86/events/intel/uncore_snb.c +++ b/arch/x86/events/intel/uncore_snb.c @@ -325,7 +325,7 @@ static struct intel_uncore_ops icl_uncore_msr_ops = { static struct intel_uncore_type icl_uncore_cbox = { .name = "cbox", - .num_counters = 4, + .num_counters = 2, .perf_ctr_bits = 44, .perf_ctr = ICL_UNC_CBO_0_PER_CTR0, .event_ctl = SNB_UNC_CBO_0_PERFEVTSEL0,