bus: arm-ccn: Move event cleanup routine

Commit Message

Pawel Moll Sept. 2, 2014, 3:26 p.m. UTC

From: Pawel Moll <[e-mail]>

The function cleaning up an initialized event
was called from the "event_del" handler, instead
of being used as the "destroy" callback. In case of
events group allocation this caused NULL pointer
dereference (as events are added and deleted
multiple times then). Fixed now.

Signed-off-by: Pawel Moll <[e-mail]>
---
 drivers/bus/arm-ccn.c | 51 +++++++++++++++++++++++++--------------------------
 1 file changed, 25 insertions(+), 26 deletions(-)

Comments

Kevin Hilman Sept. 5, 2014, 8:27 p.m. UTC | #1

Pawel Moll <[e-mail]> writes:

> From: Pawel Moll <[e-mail]>
>
> The function cleaning up an initialized event
> was called from the "event_del" handler, instead
> of being used as the "destroy" callback. In case of
> events group allocation this caused NULL pointer
> dereference (as events are added and deleted
> multiple times then). Fixed now.
>
> Signed-off-by: Pawel Moll <[e-mail]>

Applied to fixes,

Thanks,

Kevin

Patch

diff --git a/drivers/bus/arm-ccn.c b/drivers/bus/arm-ccn.c
index 6f550d9..a60f264 100644
--- a/drivers/bus/arm-ccn.c
+++ b/drivers/bus/arm-ccn.c
@@ -586,6 +586,30 @@  static int arm_ccn_pmu_type_eq(u32 a, u32 b)
 	return 0;
 }
 
+static void arm_ccn_pmu_event_destroy(struct perf_event *event)
+{
+	struct arm_ccn *ccn = pmu_to_arm_ccn(event->pmu);
+	struct hw_perf_event *hw = &event->hw;
+
+	if (hw->idx == CCN_IDX_PMU_CYCLE_COUNTER) {
+		clear_bit(CCN_IDX_PMU_CYCLE_COUNTER, ccn->dt.pmu_counters_mask);
+	} else {
+		struct arm_ccn_component *source =
+				ccn->dt.pmu_counters[hw->idx].source;
+
+		if (CCN_CONFIG_TYPE(event->attr.config) == CCN_TYPE_XP &&
+				CCN_CONFIG_EVENT(event->attr.config) ==
+				CCN_EVENT_WATCHPOINT)
+			clear_bit(hw->config_base, source->xp.dt_cmp_mask);
+		else
+			clear_bit(hw->config_base, source->pmu_events_mask);
+		clear_bit(hw->idx, ccn->dt.pmu_counters_mask);
+	}
+
+	ccn->dt.pmu_counters[hw->idx].source = NULL;
+	ccn->dt.pmu_counters[hw->idx].event = NULL;
+}
+
 static int arm_ccn_pmu_event_init(struct perf_event *event)
 {
 	struct arm_ccn *ccn;
@@ -599,6 +623,7 @@  static int arm_ccn_pmu_event_init(struct perf_event *event)
 		return -ENOENT;
 
 	ccn = pmu_to_arm_ccn(event->pmu);
+	event->destroy = arm_ccn_pmu_event_destroy;
 
 	if (hw->sample_period) {
 		dev_warn(ccn->dev, "Sampling not supported!\n");
@@ -731,30 +756,6 @@  static int arm_ccn_pmu_event_init(struct perf_event *event)
 	return 0;
 }
 
-static void arm_ccn_pmu_event_free(struct perf_event *event)
-{
-	struct arm_ccn *ccn = pmu_to_arm_ccn(event->pmu);
-	struct hw_perf_event *hw = &event->hw;
-
-	if (hw->idx == CCN_IDX_PMU_CYCLE_COUNTER) {
-		clear_bit(CCN_IDX_PMU_CYCLE_COUNTER, ccn->dt.pmu_counters_mask);
-	} else {
-		struct arm_ccn_component *source =
-				ccn->dt.pmu_counters[hw->idx].source;
-
-		if (CCN_CONFIG_TYPE(event->attr.config) == CCN_TYPE_XP &&
-				CCN_CONFIG_EVENT(event->attr.config) ==
-				CCN_EVENT_WATCHPOINT)
-			clear_bit(hw->config_base, source->xp.dt_cmp_mask);
-		else
-			clear_bit(hw->config_base, source->pmu_events_mask);
-		clear_bit(hw->idx, ccn->dt.pmu_counters_mask);
-	}
-
-	ccn->dt.pmu_counters[hw->idx].source = NULL;
-	ccn->dt.pmu_counters[hw->idx].event = NULL;
-}
-
 static u64 arm_ccn_pmu_read_counter(struct arm_ccn *ccn, int idx)
 {
 	u64 res;
@@ -1027,8 +1028,6 @@  static int arm_ccn_pmu_event_add(struct perf_event *event, int flags)
 static void arm_ccn_pmu_event_del(struct perf_event *event, int flags)
 {
 	arm_ccn_pmu_event_stop(event, PERF_EF_UPDATE);
-
-	arm_ccn_pmu_event_free(event);
 }
 
 static void arm_ccn_pmu_event_read(struct perf_event *event)