From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 C1BC336EAA6 for ; Wed, 1 Jul 2026 21:46:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782942381; cv=none; b=LEF0XCoOHcpSzQb2hY6hwgAJb8cdpocnSfkQNoXLUn3hKmuedK1l7QFkS+xZKSx78QEMIrNU658pIl37DT/GkhfczsqjiMwpIpDya/+8OpTxZNBiMoS9ikmKBlPYAmoKCKzI8c+xqicdXXwmJfKvbUwSeETyyR0IWRh7UhXCWoI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782942381; c=relaxed/simple; bh=taoTAW3XfjlX41o+x2NzgB5ymzZXYu+oGNSovsEMrqM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=UlhdRwkCFNtbvGEh2d1jO2ZO/4g9VnLV4l0WaAAdj7oKuaojlEd/jSHyAZo10LSuntqmfwpDQBjAhhQOUHgjutW1pnW0p/Ow4YaAx1SOZbhp7Hs51N56Ixvn/bBeDUa3ibsO9oMIZzR+4etYEUzSeujnbb9G1hz7zmM93sgttTE= 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=YdecdKhx; arc=none smtp.client-ip=209.85.214.202 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="YdecdKhx" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2ca3b314193so13998015ad.1 for ; Wed, 01 Jul 2026 14:46:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782942379; x=1783547179; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=qtYY9477XtQSo118z31EWp3I9HxqttwyWrA0etPzev0=; b=YdecdKhxTY4BLPvtOWnldwFgw9Y1iPBvs7qW0Zu3OSN31591rb+xlt4CWKjlz1ZqSX O1GN5G5sxsbUxVFmnb702BK8sG6/d++BErh5MuP/UCwycod07bahfGm9K7Q+DRrfbHIN wCnWse/oH6UFryBf2uZEis01/xsBJBS2Gs6V7O0nqkrCN9K4hEoXQ6Lg2QmDxq2FTHF6 wNRZ2AuCULfDEqGsYoTl3gjkMKzTv+A9tBwBfaNUZHA1nTAHcimD+x3LGTTHqe+EXiRB 4T/+uNQvyvSKoBYvr1TqzQitfgvt3wNaf6XWJnM0cMru1raatw/Bps/N4hYs00wX9Ngv qCKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782942379; x=1783547179; h=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; bh=qtYY9477XtQSo118z31EWp3I9HxqttwyWrA0etPzev0=; b=FxeBctFCSg2UO3S7C6RdBJiGce/LH+n0kFlz7v+nEulPOLGeMNZzAfRrMyLPCV0Hud JTPMytiUlEB3F40KdNHF16gXVFLP16CSfXGn+vLlqBvsgiudbN28sUuGJ9DxUVA9e0Tb cd+Zvwdynll4CYSvFX7pzmm+aVH7vXH5+PeqEdRssrwp4ZktDedPLWfyoqOE5jGauElu XPSql3i0M6zDgeJaSN4jodugLjM51/Op8GxngzvL3fjl2eh6OnbfBj/g9MVIC/98nAIk H3fM5qyxobFq1EcTiXzv4fwC2o7iDC8rcKuIum1LBXBlXOTTDzxI7ADUI+edwNcQy0GF PoAQ== X-Gm-Message-State: AOJu0YxmbbUVTDPuexF2LQxtROoI7tTpq9H1AxM1sz3+CZUyVIerLls/ 64ACQPlChGcRcUIPojzudir7YMj7cfCBRh9j6mu8yws+lHFqNhH0e0t4Y5DC3Y0ZqNoiWn39viE hISh0KCkYOH+20RgPjDOJF/EKyMpzhZKe64knazhJLxdNlXmq8lE/5nQJKJeNjvcRJUjPXzNy49 3IOgb/3avJdz6BHdi1KkNwmQUP+m65cjPkqOiY8efauFSNnAff X-Received: from plbkt8.prod.google.com ([2002:a17:903:888:b0:2b0:51f0:272d]) (user=jstultz job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:f60e:b0:2ca:2e9:c8e9 with SMTP id d9443c01a7336-2ca7e8db6e5mr34431495ad.24.1782942378762; Wed, 01 Jul 2026 14:46:18 -0700 (PDT) Date: Wed, 1 Jul 2026 21:45:56 +0000 In-Reply-To: <20260701214615.3773339-1-jstultz@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260701214615.3773339-1-jstultz@google.com> X-Mailer: git-send-email 2.55.0.rc0.799.gd6f94ed593-goog Message-ID: <20260701214615.3773339-2-jstultz@google.com> Subject: [PATCH v30 1/7] 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 , 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: kuyo chang Cc: hupu Cc: Vasily Gorbik 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.rc0.799.gd6f94ed593-goog