From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793896266; b=wNXISi89gke+m03ZeJ0tl0VVTL8zzsOp7UrugYHvZAAeGvqmNTFOueCbot7EEZ0qG75g t14nE6VXQPB9oE1xehHersldoV5UEFJwxzZPcDn7nbmO70TYrVKAqreghmuFEXi/SI4Gx 38SFHmqu5Oj6/wc+JDbBJOjG7IxHjob8NCX7QpGTyAoyYKUDwSz43WtAD1+tYa6SBvOXa hbCLaEhwu7E855AIPSwqX/E/x0mA3kxIv5ID1KuZ7kF7eb06zS2fw6uahVc0oUzC3sU2m Osf+RVxRlKQfIBUOqi69rBV71X0NM5prXxxPiohmiGh8LBCT7ALoLyKZ324IKGeX+Dw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793896266; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=Igc7YNMSkmyhxBWcCj38Xzf5geNbKdbWlTqxE7SW6oY=; b=PweDKkOPoiILP3n8egpdGqnvIIFRFAJwUOf32Dr94/Tjz6lKiFAZ0mYrMNaalQAngiEa GaGG38dPtff3QnRIabFpsKHnqSFx+GEMmVNSnngZCVIaNg4ZQTTUm+gCaL11I0SA02irT 3Xyqf57/z136c6ixdZZz0czMQ4o9jwNOmHMZJZDuCoXifAi6f7GviaiHYKAhfUHwatlk7 LDlMdPlvsYIc+4RGTL7FwnEG/yiNM2bO3qnWmxeVWq2BmHazjbbmeKpx7ce0ktHPK4c2b a5OFAa2CVfF26Dua867LyAp0M+lzirX4lR0A3ptsP0pLLLzM+VlRuIDZNeB9JmW/Ybg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DSRa5aRQ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7682E6083632 for ; Thu, 5 Nov 2026 16:31:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DSRa5aRQ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 250741F00919; Thu, 5 Nov 2026 16:31:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793896266; bh=Igc7YNMSkmyhxBWcCj38Xzf5geNbKdbWlTqxE7SW6oY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DSRa5aRQ/tTmY4A3euol0yR6DBtf+WgKwrNaqiAm4mmteUR3S3ybchHNVY4J5E2Ug ARclXaUIppZCtdPU/6xdfN1XlXktT12PUrPwzL59L9p7xM7KvZYiiO4zHYAjh+MVTz 47ELvjFKSUibYo7R8BjklYWdAM6dHcYCtYZzjzdxhiT67ClstZbwgb1wk9FnCM629k cG7MV8u8ANya9HXzy0edHG5KdNK9Hxc/x2F8n+H3Lw0AeOMDpdHfeCBFRawWbCFsg9 bkpo9KBbTcqibALVtT3wztSd9tMIeKUnO2YoUkPGF68OFFMImMQoqCsfA0iDg2/V6g 3dVKUcW2E017w== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Marco Crivellari , Peter Zijlstra , Phil Auld , Thomas Gleixner , Waiman Long , "Paul E. McKenney" Subject: [PATCH 04/47] rcu: Move CPUHP_AP_RCUTREE_DYING to post stop_machine() Date: Thu, 5 Nov 2026 17:30:02 +0100 Message-ID: <20261105163045.38862-5-frederic@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261105163045.38862-1-frederic@kernel.org> References: <20261105163045.38862-1-frederic@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Between CPUHP_TEARDOWN_CPU and CPUHP_AP_OFFLINE, stop_machine executes all the teardown callbacks while stopping all CPUs in the system. This doesn't mix-up well with running RT or isolated tasks. In order to transition smoothly from global stop_machine to finer grained synchronization between teardown callbacks and the other CPUs, a new stop machine post function has been introduced to be executed after the main one with IRQs still disabled while other CPUs can exit stop_machine(). Here RCU just does tracing with already proper handling of racy accesses. Move this teardown callback to post stop_machine() accordingly. Signed-off-by: Frederic Weisbecker --- kernel/cpu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 6e6d3a3016a5..58bb74f0fcb0 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1275,7 +1275,7 @@ void clear_tasks_mm_cpumask(int cpu) static int take_cpu_down(void *_param) { struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); - enum cpuhp_state target = max((int)st->target, CPUHP_AP_SCHED_STARTING); + enum cpuhp_state target = max((int)st->target, CPUHP_AP_RCUTREE_DYING); int err, cpu = smp_processor_id(); /* Ensure this CPU doesn't handle any more interrupts. */ @@ -1303,7 +1303,7 @@ static int take_cpu_down_post(void *_param) enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); int cpu = smp_processor_id(); - WARN_ON(st->state != CPUHP_AP_SCHED_STARTING); + WARN_ON(st->state != CPUHP_AP_RCUTREE_DYING); /* * Invoke the former CPU_DYING callbacks. DYING must not fail! */ -- 2.53.0