From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 923EC54781 for ; Fri, 7 Aug 2026 03:52:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786074759; cv=none; b=t4H+aL/RRDFjwstr6uzCDD1oO9+qtnEWfa8gTTv5d+Zx99OW+MGHonfjTJDHB5nn99vdjAla3T0JzcFEbhNX8LSTYVZ+Wc3A27njpRniRG73s7TpDHFC34xYHlQekb9GVWViP1vahdAwO9swuuxr1wxAJCT1qDLGnZL5Vn0vXCI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786074759; c=relaxed/simple; bh=BveIFHm8f1pxHIEtlh4aRe8r6xMPj1s9NARTeBSlw4c=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=r8YsyRWVZNFEks10iG7+vKgWuohOahuyuoJgY7L8oKBw3bJtlzW5fEXGBsYifKC83HxAhzCXp9/nsmfJVoLytcER7pjhA5tBTHp/hUOuKJYl75zoeSiL9bdyIkcvpnEPEaf7rHTlqbW8pVya8aezz3pstFGXoiwin2B6Sci2TCM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=AYuGXELe; arc=none smtp.client-ip=209.85.210.198 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="AYuGXELe" Received: by mail-pf1-f198.google.com with SMTP id d2e1a72fcca58-8488ac68185so7154427b3a.2 for ; Thu, 06 Aug 2026 20:52:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786074757; x=1786679557; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=nOytJ7VS6kPnWFg638bBnd067nfAO6608KAQO4VuI2U=; b=AYuGXELeqIHyCD/LnXjtvUNByltj5oMbFnZ7Jxz4E5ptR1IduKRZRCxHvZ/3u2tjQe 6W2D5yqvwE4yYA2ngcfesjT5OmUYSwIduESrcH1fA2n22ojGccYPLU23u+U056woBzge jsEW/hFxT5hmwuHho28m238YsPBkPp3hglHTDZWWVGXgW9mHIbBsvGltrRzCXS2j3dYW fet9SjXcq06N35V2Gg0qZDpq2MQOqO/CuXfs/bxIcgYf3dPxudXjgwJhC1co8YtC3lH4 VHtim8QOo5Zw8rbO85CRwYl3t9pv20nxlzOc+iTihoSZrfGzP6sYIV74w8cC9sIqK6iT q4Sg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786074757; x=1786679557; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=nOytJ7VS6kPnWFg638bBnd067nfAO6608KAQO4VuI2U=; b=iucLz6nuvd9iIrHUUEZ3KCU94Yf6VKnfducdAX6hGcxm9DGxnIvvimH71KnMNJS3O5 DaMTgGrIditoeOHqiuJ3Z6AV8ImX0iYXl32Am5nw8p/lpEcIZDLe8oSDjTiXcAFDAeMw fIngxpvc/3ovzNFukkHqGPRgmDhjDyBW49v6xzEDYuwi5Lze72zKyCLlSkIu9U7An6du oqh+op0qvLA6qyZ2ZbvuJka/+e45b+tC3XUO9pZxIZZdrjJnOcZljCkmmcR9upPbVdLG pmUlB/fM00DoWRCig9DgrrCSBCQckW4kn2xa9Zpcl6x3VyVgvmn7xktxkxcwCxv4bLZ4 s/EQ== X-Gm-Message-State: AOJu0Yw1jNkGA3E6ni0+QWgzDc5yW7JI+IR4WuEW0FlKKrHv6qYlwk1G qQoWKXf4lb3xtIdGpusuEX5SiDMwr8wPgWodz7+5zl7VsBHBFU3v6Laye9tN+bRqQ2WimWd55Tf oZL54eiSpY6xC0I6NGLnNC0VxKoUrrIY7IcfNvvh+17Fin3aO1paxCE6PuMJB9RUQcR8IDKpSHq zE7OCEwOweMrOFd0jLiY7zYL1O3Yx66xBa9ZpgR9/n91d1CJev X-Received: from pfbeb25.prod.google.com ([2002:a05:6a00:4c99:b0:848:49f6:6f5c]) (user=jstultz job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:298e:b0:845:dffa:3740 with SMTP id d2e1a72fcca58-84f2e0151aemr24279859b3a.4.1786074756345; Thu, 06 Aug 2026 20:52:36 -0700 (PDT) Date: Fri, 7 Aug 2026 03:52:08 +0000 In-Reply-To: <20260807035232.1881495-1-jstultz@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260807035232.1881495-1-jstultz@google.com> X-Mailer: git-send-email 2.55.0.654.g21b8a5bc05-goog Message-ID: <20260807035232.1881495-3-jstultz@google.com> Subject: [RESEND][PATCH v31 2/9] sched/core: Don't steal a proxy-exec donor From: John Stultz To: LKML Cc: Vasily Gorbik , John Stultz , Joel Fernandes , Qais Yousef , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Valentin Schneider , Steven Rostedt , Ben Segall , Zimuzo Ezeozue , Will Deacon , Waiman Long , Boqun Feng , "Paul E. McKenney" , Metin Kaya , Xuewen Yan , K Prateek Nayak , Thomas Gleixner , Daniel Lezcano , Suleiman Souhlal , Andrea Righi , kuyo chang , hupu , kernel-team@android.com Content-Type: text/plain; charset="UTF-8" From: Vasily Gorbik try_steal_cookie() avoids stealing src->core_pick and src->curr before moving a task with the same cookie via move_queued_task_locked(). With proxy-exec, src->donor is the current scheduling context and may differ from src->curr. Stealing it migrates a task that the source rq still treats as current, leaving src's scheduler state for that task stale. For CFS this means cfs_rq->curr points at the stolen entity, and the next pick on the source rq hits the WARN_ON_ONCE in put_prev_entity(). Commit 7de9d4f94638 ("sched: Start blocked_on chain processing in find_proxy_task()") tweaked the fair class logic so that the donor task isn't migrated away while we're running the proxy. Do it similarly for try_steal_cookie() and skip src->donor as well. Fixes: 7de9d4f94638 ("sched: Start blocked_on chain processing in find_proxy_task()") Signed-off-by: Vasily Gorbik Signed-off-by: John Stultz --- Cc: Joel Fernandes Cc: Qais Yousef Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Valentin Schneider Cc: Steven Rostedt Cc: Ben Segall Cc: Zimuzo Ezeozue Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng Cc: "Paul E. McKenney" Cc: Metin Kaya Cc: Xuewen Yan Cc: K Prateek Nayak Cc: Thomas Gleixner Cc: Daniel Lezcano Cc: Suleiman Souhlal Cc: Andrea Righi Cc: kuyo chang Cc: hupu Cc: kernel-team@android.com --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 96226707c2f61..e7074ba54a91f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6474,7 +6474,7 @@ static bool try_steal_cookie(int this, int that) return false; do { - if (p == src->core_pick || p == src->curr) + if (p == src->core_pick || p == src->curr || p == src->donor) goto next; if (!is_cpu_allowed(p, this)) -- 2.55.0.654.g21b8a5bc05-goog