perf/arm-dmc620: Fix lockdep assert in ->event_init()

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>

diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c
index 2ec96e204c403ec7b3403561433ccddf97fbb743..7e5f1d4fca0f170e04a370583b5e4bb4983b11ce 100644 (file)
--- a/drivers/perf/arm_dmc620_pmu.c
+++ b/drivers/perf/arm_dmc620_pmu.c
@@ -542,12 +542,16 @@ 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) {
@@ -556,7 +560,6 @@ static int dmc620_pmu_event_init(struct perf_event *event)
                        return -EINVAL;
        }
 
-       hwc->idx = -1;
        return 0;
 }