From: Tejun Heo <tj@kernel.org>
Date: Fri, 13 Jun 2025 23:23:07 +0000 (-1000)
Subject: sched_ext: Make scx_group_set_weight() always update tg->scx.weight
X-Git-Tag: v6.16-rc3~33^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c50784e99f0e7199cdb12dbddf02229b102744ef;p=thirdparty%2Flinux.git

sched_ext: Make scx_group_set_weight() always update tg->scx.weight

Otherwise, tg->scx.weight can go out of sync while scx_cgroup is not enabled
and ops.cgroup_init() may be called with a stale weight value.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 819513666966 ("sched_ext: Add cgroup support")
Cc: stable@vger.kernel.org # v6.12+
---

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 2c41c78be61eb..33a0d8c6ff95f 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -4241,12 +4241,12 @@ void scx_group_set_weight(struct task_group *tg, unsigned long weight)
 
 	percpu_down_read(&scx_cgroup_rwsem);
 
-	if (scx_cgroup_enabled && tg->scx_weight != weight) {
-		if (SCX_HAS_OP(sch, cgroup_set_weight))
-			SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_set_weight, NULL,
-				    tg_cgrp(tg), weight);
-		tg->scx_weight = weight;
-	}
+	if (scx_cgroup_enabled && SCX_HAS_OP(sch, cgroup_set_weight) &&
+	    tg->scx_weight != weight)
+		SCX_CALL_OP(sch, SCX_KF_UNLOCKED, cgroup_set_weight, NULL,
+			    tg_cgrp(tg), weight);
+
+	tg->scx_weight = weight;
 
 	percpu_up_read(&scx_cgroup_rwsem);
 }