sched/core: Add clearing of ->dl_server in put_prev_task_balance()

Paths using put_prev_task_balance() need to do a pick shortly
after. Make sure they also clear the ->dl_server on prev as a
part of that.

Fixes: 63ba8422f876 ("sched/deadline: Introduce deadline servers")
Signed-off-by: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/d184d554434bedbad0581cb34656582d78655150.1716811044.git.bristot@kernel.org

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0a71050f5f0dd279979cbabe39e94ab3707c88df..e61da3b88be31c549c9213e9fa7b2bf3562e3962 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5801,6 +5801,14 @@ static void put_prev_task_balance(struct rq *rq, struct task_struct *prev,
 #endif
 
        put_prev_task(rq, prev);
+
+       /*
+        * We've updated @prev and no longer need the server link, clear it.
+        * Must be done before ->pick_next_task() because that can (re)set
+        * ->dl_server.
+        */
+       if (prev->dl_server)
+               prev->dl_server = NULL;
 }
 
 /*
@@ -5844,14 +5852,6 @@ __pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 restart:
        put_prev_task_balance(rq, prev, rf);
 
-       /*
-        * We've updated @prev and no longer need the server link, clear it.
-        * Must be done before ->pick_next_task() because that can (re)set
-        * ->dl_server.
-        */
-       if (prev->dl_server)
-               prev->dl_server = NULL;
-
        for_each_class(class) {
                p = class->pick_next_task(rq);
                if (p)