From: Namhyung Kim <namhyung@kernel.org>
Date: Tue, 14 May 2024 18:00:50 +0000 (-0700)
Subject: perf/arm-dmc620: Fix lockdep assert in ->event_init()
X-Git-Tag: v6.10-rc1~38^2~3
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=a4c5a457c6107dfe9dc65a104af1634811396bac;p=linux-2.6-block.git

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 2ec96e204c40..7e5f1d4fca0f 100644
--- 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;
 }