From: Peter Zijlstra <peterz@infradead.org>
To: John Stultz <jstultz@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
Qais Yousef <qyousef@layalina.io>, Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Valentin Schneider <vschneid@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>,
Zimuzo Ezeozue <zezeozue@google.com>,
Will Deacon <will@kernel.org>, Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Metin Kaya <Metin.Kaya@arm.com>,
Xuewen Yan <xuewen.yan94@gmail.com>,
K Prateek Nayak <kprateek.nayak@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Suleiman Souhlal <suleiman@google.com>,
kuyo chang <kuyo.chang@mediatek.com>, hupu <hupu.gm@gmail.com>,
kernel-team@android.com
Subject: Re: [PATCH v29 5/9] sched: Have try_to_wake_up() handle return-migration for PROXY_WAKING case
Date: Fri, 22 May 2026 13:30:54 +0200 [thread overview]
Message-ID: <20260522113054.GO3126523@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20260512025635.2840817-6-jstultz@google.com>
On Tue, May 12, 2026 at 02:56:15AM +0000, John Stultz wrote:
> migrate_task:
> proxy_migrate_task(rq, rf, p, owner_cpu);
> @@ -7107,6 +7101,9 @@ static void __sched notrace __schedule(int sched_mode)
> if (sched_proxy_exec()) {
> struct task_struct *prev_donor = rq->donor;
>
> + if (!prev_state && prev->blocked_on)
> + clear_task_blocked_on(prev, NULL);
> +
> rq_set_donor(rq, next);
> if (unlikely(next->blocked_on)) {
> next = find_proxy_task(rq, next, &rf);
This adds a @prev dereference, after you've just explained how we should
not use @prev after a lock break.
next prev parent reply other threads:[~2026-05-22 11:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-12 2:56 [PATCH v29 0/9] Optimized Donor Migration for Proxy Execution John Stultz
2026-05-12 2:56 ` [PATCH v29 1/9] sched: Rework pick_next_task() and prev_balance() to avoid stale prev references John Stultz
2026-05-19 10:32 ` Peter Zijlstra
2026-05-20 2:45 ` John Stultz
2026-05-20 9:43 ` Peter Zijlstra
2026-06-04 18:45 ` [tip: sched/core] sched: Rework " tip-bot2 for John Stultz
2026-05-12 2:56 ` [PATCH v29 2/9] sched: deadline: Add some helper variables to cleanup deadline logic John Stultz
2026-06-04 18:45 ` [tip: sched/core] " tip-bot2 for John Stultz
2026-05-12 2:56 ` [PATCH v29 3/9] sched: deadline: Add dl_rq->curr pointer to address issues with Proxy Exec John Stultz
2026-06-04 18:45 ` [tip: sched/core] " tip-bot2 for John Stultz
2026-05-12 2:56 ` [PATCH v29 4/9] sched: Rework block_task so it can be directly called John Stultz
2026-06-04 18:45 ` [tip: sched/core] " tip-bot2 for John Stultz
2026-05-12 2:56 ` [PATCH v29 5/9] sched: Have try_to_wake_up() handle return-migration for PROXY_WAKING case John Stultz
2026-05-22 11:30 ` Peter Zijlstra [this message]
2026-05-22 11:35 ` Peter Zijlstra
2026-06-04 18:45 ` [tip: sched/core] " tip-bot2 for John Stultz
2026-05-12 2:56 ` [PATCH v29 6/9] sched: Add is_blocked task flag John Stultz
2026-06-04 18:45 ` [tip: sched/core] " tip-bot2 for John Stultz
2026-05-12 2:56 ` [PATCH v29 7/9] sched: Add blocked_donor link to task for smarter mutex handoffs John Stultz
2026-05-19 14:32 ` Peter Zijlstra
2026-05-19 14:46 ` Peter Zijlstra
2026-05-19 15:46 ` K Prateek Nayak
2026-05-20 18:10 ` John Stultz
2026-05-22 9:50 ` Peter Zijlstra
2026-05-20 18:09 ` John Stultz
2026-06-04 18:45 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2026-05-12 2:56 ` [PATCH v29 8/9] sched: Break out core of attach_tasks() helper into sched.h John Stultz
2026-05-12 2:56 ` [PATCH v29 9/9] sched: Migrate whole chain in proxy_migrate_task() John Stultz
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