From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) (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 D3DFA372B27 for ; Fri, 24 Jul 2026 18:12:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784916766; cv=none; b=KNjYlj7vLsRXXOVMkv6Cnsx1uA/WswvO15qq4eyAuZ+VTaDt6JGZY+rzihj6+TImdiulP2Sxkr+BQRGw4CQhzGex638p24ah/jyDox+MLZTUJa/lzVrjF3FyJTHOf+KJEKF3XJzRE+doBfeYG/i4iyglVf4TVIxI9+5hK3NoLes= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784916766; c=relaxed/simple; bh=gwBHrcBppSr7kgKgReFU0s7XkMcqC9NKaO0MOP/ng3Y=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=B4cDo2L5yDQj7Tm+n9/Z0IbG4waeVeItinYv2VkRIt6QenfRB4arVZai1/80D/77GInTwS9h2CrHAO8dT9snNRyUz5lCXCjuicVS01PLsPB4+oCmSAFVPSSnqZBp0sfbm9Qvre6V9dAa1ffAP5/tF8YHNSQGpFG3kM8S+5ga3R4= 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=FPnp84cp; arc=none smtp.client-ip=209.85.214.200 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="FPnp84cp" Received: by mail-pl1-f200.google.com with SMTP id d9443c01a7336-2ccb6823efcso6538845ad.0 for ; Fri, 24 Jul 2026 11:12:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1784916764; x=1785521564; 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=J7OIU3r/UTkoP1uvZH3CR6gme4w4msMs0MeYe2vy4AU=; b=FPnp84cprBgFzAejjlBdycaJKwKUywzbT4LAJDGvOtKkhtEaVwTpcRo9fWkkvJ553Y eAR014VeA+jPP61vKK/jAkfCKfI5tWlScFvWFMEVlFFyYi2/Ns2qelhFmOoA24MyhF/H 7GeAmfama5/Iagc9gNQ2KmGUTpwBMrXRpDeaYIwl0dtqeRqw5x2n65qktCOtI8YuCQap ARlIPO4NdBDTxwETMZYcOzQ6UA5hgvJaez4nDvhcT7nGd0XL72I6fUGN1oSgJ5nyWYTW RGCKY/2mhnPfKmISPrRTeZMJqkuVjEFN3CX2BseAoAwA4r9w0zL5QEDaq2cxOmuLIokP BXvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784916764; x=1785521564; 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=J7OIU3r/UTkoP1uvZH3CR6gme4w4msMs0MeYe2vy4AU=; b=os3Ejg9rxwQu8gHMqqpfnQANMgHtFcp+B5SsIn0ZSu8RdOz68Y/5Whvb74cFwfELoH IWTpENtfoUimyteL2kmBNkd3uOsxDaT/4eM67+PVTgMHQbYI5jN4juJQEr/6+/yQf3Bj 3u6je2j0zboVN4eq24sUFUZjJMzKmMvO2pgQVZg2ug7ZULPvF+SpDyO//cNBHScs7/iw Ec8rY76LreoYJkFAyU8Qf/Mr/Ta9t9xBoAdFBjHZ7Hq6XWs3bwreXJ7EqT3cLASUWuFf LbL8AMxQ+pu74JjMQv5QvsalPdz7ODcKijiETSNCxJV9TaXPZIx4+6xf7931AFZ2w8x9 FT6w== X-Gm-Message-State: AOJu0YyQCMQjh8d1BWLusesh9t5xSLuu76QIEUY9YcgBSwDzGduUllxe i6YKbbg1WwrEAhXPSJs2m1ijLacOfx6g1A+W3xSZX9xxfGumKHcMy3B4CSbvZGhLoJaJKIwzlL6 kFaUcqD3CkTksRXWhjmCuRS/1yKfSxiLbXC1qjrF7tT/4L2LocxFwAsnRV2isRoY2vWVmK4QfPC SC+nX7InjMEVeDjQSPvdJWXLLG5kymwMh0bXaDcLCzNjpGN1QR X-Received: from pla11.prod.google.com ([2002:a17:902:ffcb:b0:2cc:e407:8fef]) (user=jstultz job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:1c3:b0:2ce:d34a:5959 with SMTP id d9443c01a7336-2cfa6f97cedmr92633065ad.44.1784916763734; Fri, 24 Jul 2026 11:12:43 -0700 (PDT) Date: Fri, 24 Jul 2026 18:12:16 +0000 In-Reply-To: <20260724181238.3445275-1-jstultz@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260724181238.3445275-1-jstultz@google.com> X-Mailer: git-send-email 2.55.0.229.g6434b31f56-goog Message-ID: <20260724181238.3445275-3-jstultz@google.com> Subject: [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)) -- 2.55.0.229.g6434b31f56-goog