Patch "perf/arm-dmc620: Fix lockdep assert in ->event_init()" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-arm-dmc620-fix-lockdep-assert-in-event_init.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 84d1d3b78dc4a2426d4ea2f7ffaaf56b034ca4fc
Author: Namhyung Kim <namhyung@xxxxxxxxxx>
Date:   Tue May 14 11:00:50 2024 -0700

    perf/arm-dmc620: Fix lockdep assert in ->event_init()
    
    [ 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@xxxxxxx>
    Fixes: f3c0eba28704 ("perf: Add a few assertions")
    Reported-by: Greg Thelen <gthelen@xxxxxxxxxx>
    Cc: Robin Murphy <robin.murphy@xxxxxxx>
    Cc: Tuan Phan <tuanphan@xxxxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
    Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
    Link: https://lore.kernel.org/r/20240514180050.182454-1-namhyung@xxxxxxxxxx
    Signed-off-by: Will Deacon <will@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c
index 30cea68595747..b6a677224d682 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;
 }