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Subject[PATCH 3/3] perf/x86/intel/uncore: Reduce the number of CBOX counters
Date
From: Kan Liang <kan.liang@linux.intel.com>

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] <IRQ>
[ 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 <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,
--
2.17.1
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