[tip: perf/core] perf/x86/intel/uncore: Fix refcnt and other cleanups

[tip-bot2 for Zide Chen]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     7d3a9ff98898b3521eb5d7a3daf703b383f7935a
Gitweb:        https://git.kernel.org/tip/7d3a9ff98898b3521eb5d7a3daf703b383f7935a
Author:        Zide Chen <zide.chen@xxxxxxxxx>
AuthorDate:    Thu, 11 Jun 2026 09:00:27 -07:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 30 Jun 2026 10:57:03 +02:00

perf/x86/intel/uncore: Fix refcnt and other cleanups

Fix typo UNCORE_BOX_FLAG_INITIATED to UNCORE_BOX_FLAG_INITIALIZED.

Rename the 'id' parameter in uncore_box_{ref,unref}() to 'die' to
reflect its actual meaning and be consistent with other functions.

box->refcnt is incremented in the PCI PMU register path but has never
been checked or decremented. Although for PCI PMUs box->refcnt
effectively tracks only a single user, add atomic_dec_return() in the
PCI PMU unregister path to make the reference counting complete and
consistent.

Signed-off-by: Zide Chen <zide.chen@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
Link: https://patch.msgid.link/20260611160033.66760-3-zide.chen@xxxxxxxxx
---
 arch/x86/events/intel/uncore.c | 16 +++++++++-------
 arch/x86/events/intel/uncore.h |  6 +++---
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index b69b6a2..21c8ed1 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -1255,8 +1255,10 @@ static void uncore_pci_pmu_unregister(struct intel_uncore_pmu *pmu, int die)
 	pmu->boxes[die] = NULL;
 	if (atomic_dec_return(&pmu->activeboxes) == 0)
 		uncore_pmu_unregister(pmu);
-	uncore_box_exit(box);
-	kfree(box);
+	if (atomic_dec_return(&box->refcnt) == 0) {
+		uncore_box_exit(box);
+		kfree(box);
+	}
 }
 
 static void uncore_pci_remove(struct pci_dev *pdev)
@@ -1518,7 +1520,7 @@ static void uncore_change_context(struct intel_uncore_type **uncores,
 		uncore_change_type_ctx(*uncores, old_cpu, new_cpu);
 }
 
-static void uncore_box_unref(struct intel_uncore_type **types, int id)
+static void uncore_box_unref(struct intel_uncore_type **types, int die)
 {
 	struct intel_uncore_type *type;
 	struct intel_uncore_pmu *pmu;
@@ -1529,7 +1531,7 @@ static void uncore_box_unref(struct intel_uncore_type **types, int id)
 		type = *types;
 		pmu = type->pmus;
 		for (i = 0; i < type->num_boxes; i++, pmu++) {
-			box = pmu->boxes[id];
+			box = pmu->boxes[die];
 			if (box && box->cpu >= 0 && atomic_dec_return(&box->refcnt) == 0)
 				uncore_box_exit(box);
 		}
@@ -1604,14 +1606,14 @@ cleanup:
 }
 
 static int uncore_box_ref(struct intel_uncore_type **types,
-			  int id, unsigned int cpu)
+			  int die, unsigned int cpu)
 {
 	struct intel_uncore_type *type;
 	struct intel_uncore_pmu *pmu;
 	struct intel_uncore_box *box;
 	int i, ret;
 
-	ret = allocate_boxes(types, id, cpu);
+	ret = allocate_boxes(types, die, cpu);
 	if (ret)
 		return ret;
 
@@ -1619,7 +1621,7 @@ static int uncore_box_ref(struct intel_uncore_type **types,
 		type = *types;
 		pmu = type->pmus;
 		for (i = 0; i < type->num_boxes; i++, pmu++) {
-			box = pmu->boxes[id];
+			box = pmu->boxes[die];
 			if (box && box->cpu >= 0 && atomic_inc_return(&box->refcnt) == 1)
 				uncore_box_init(box);
 		}
diff --git a/arch/x86/events/intel/uncore.h b/arch/x86/events/intel/uncore.h
index c2e5ccb..bad5d8d 100644
--- a/arch/x86/events/intel/uncore.h
+++ b/arch/x86/events/intel/uncore.h
@@ -185,7 +185,7 @@ struct intel_uncore_box {
 #define CFL_UNC_CBO_7_PERFEVTSEL0		0xf70
 #define CFL_UNC_CBO_7_PER_CTR0			0xf76
 
-#define UNCORE_BOX_FLAG_INITIATED		0
+#define UNCORE_BOX_FLAG_INITIALIZED		0
 /* event config registers are 8-byte apart */
 #define UNCORE_BOX_FLAG_CTL_OFFS8		1
 /* CFL 8th CBOX has different MSR space */
@@ -559,7 +559,7 @@ static inline u64 uncore_read_counter(struct intel_uncore_box *box,
 
 static inline void uncore_box_init(struct intel_uncore_box *box)
 {
-	if (!test_and_set_bit(UNCORE_BOX_FLAG_INITIATED, &box->flags)) {
+	if (!test_and_set_bit(UNCORE_BOX_FLAG_INITIALIZED, &box->flags)) {
 		if (box->pmu->type->ops->init_box)
 			box->pmu->type->ops->init_box(box);
 	}
@@ -567,7 +567,7 @@ static inline void uncore_box_init(struct intel_uncore_box *box)
 
 static inline void uncore_box_exit(struct intel_uncore_box *box)
 {
-	if (test_and_clear_bit(UNCORE_BOX_FLAG_INITIATED, &box->flags)) {
+	if (test_and_clear_bit(UNCORE_BOX_FLAG_INITIALIZED, &box->flags)) {
 		if (box->pmu->type->ops->exit_box)
 			box->pmu->type->ops->exit_box(box);
 	}