[PATCH 6.1 400/473] perf/arm-dmc620: Fix lockdep assert in ->event_init()

Greg Kroah-Hartman
2024-06-06T14:18:31Z

From: Namhyung Kim <namhyung@kernel.org>

[ Upstream commit a4c5a457c6107dfe9dc65a104af1634811396bac ]

for_each_sibling_event() checks leader's ctx but it doesn't have the ctx
yet if it's the leader. Like in perf_event_validate_size(), we should
skip checking siblings in that case.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Fixes: f3c0eba28704 ("perf: Add a few assertions")
Reported-by: Greg Thelen <gthelen@google.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Tuan Phan <tuanphan@os.amperecomputing.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20240514180050.182454-1-namhyung@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/perf/arm_dmc620_pmu.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c
index 54aa4658fb36e..535734dad2eb8 100644
--- a/drivers/perf/arm_dmc620_pmu.c
+++ b/drivers/perf/arm_dmc620_pmu.c
@@ -513,12 +513,16 @@ static int dmc620_pmu_event_init(struct perf_event *event)
if (event->cpu < 0)
return -EINVAL;

+ hwc->idx = -1;
+
+ if (event->group_leader == event)
+ return 0;
+
/*
* We can't atomically disable all HW counters so only one event allowed,
* although software events are acceptable.
*/
- if (event->group_leader != event &&
- !is_software_event(event->group_leader))
+ if (!is_software_event(event->group_leader))
return -EINVAL;

for_each_sibling_event(sibling, event->group_leader) {
@@ -527,7 +531,6 @@ static int dmc620_pmu_event_init(struct perf_event *event)
return -EINVAL;
}

- hwc->idx = -1;
return 0;
}

--
2.43.0