From nobody Fri Dec 19 06:34:21 2025 Received: from out162-62-58-211.mail.qq.com (out162-62-58-211.mail.qq.com [162.62.58.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96E0C1D9324; Mon, 6 Jan 2025 09:29:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.62.58.211 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736155784; cv=none; b=OEgSxTlwbwBadeJEnYAbL6sxYPp8BldcEiiivmVB18KuH+TNI6gisMHd1y1CMjswuqbKig/SauU8QvGIIRrGmzpcaPC2m3so7DfrST3epZHLfWxeylOvAj1lmo2LAk0pYHejpTgfsooJsT8spN2ikw7hGOJdBO/UBsilZn7wtzk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736155784; c=relaxed/simple; bh=rru6PLmrgyfj1x9vmlK7bt52bJgxOGXtSo7CS+zIpFw=; h=Message-ID:From:To:Cc:Subject:Date:MIME-Version; b=usa+JQpKvC4DfyrcDZAFNhMoDEWasGg//Rhtg7h4OaXdglkRrzmwbWhalUreqCA2hhLXa9w1ddZRAbwhL7I31zhJA3JjYauvEG5zJgxt8Ab8k/2HqPkDx48juXJ1+Wi+r013CUzB/y/OCedF/DEhQVL3gTrAdQUVqBGaRYGKFTU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com; spf=pass smtp.mailfrom=qq.com; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b=RrNO/dgP; arc=none smtp.client-ip=162.62.58.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=qq.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b="RrNO/dgP" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1736155468; bh=dnX7ibADsVzqp+F5wDH5DMd0+ecoDGczfnfcWBLU/oo=; h=From:To:Cc:Subject:Date; b=RrNO/dgPz2Ht7uPJBJi9qeZkiUGSI4FLkN6OkXEtzAIzIfAIcvqUj6/BR5Tvu0a01 aEhhLAXzdNC8SeYfLwr+tOZcUS8FFjPs2N4rAF7JS63zwZKf4votYDoDW01z4PqqcA oz2a2HRIXmfIEJBFwaHgwnf+gKKB7VvWZhc5hRtQ= Received: from localhost.localdomain ([101.227.46.164]) by newxmesmtplogicsvrszb16-1.qq.com (NewEsmtp) with SMTP id 61A070E8; Mon, 06 Jan 2025 17:24:26 +0800 X-QQ-mid: xmsmtpt1736155466tddbugve5 Message-ID: X-QQ-XMAILINFO: MllZffuBkEb5Ljyv7yHduB5LNU/Cx8FlR7TfEJIh/3qF28sND14RK6VJw2Cnb1 Q+4YGl1+MM9hHzuLT2WanaIp1GTXCzlibwRURMr2/tPX5ojDUKbAXlMiFmsOCC5lABRocNXSvldN MhKwMRgcqvZUk5L3FZBu+UqdLWu8mnrTegJtPEY8KMohkUxXYOT6d/DWZQ+g8RYKjIxkqCEVweEt kWzOGd7NN7/4d6OumexiicjVhi3NvlTDsZk6Z1PcIIKrho7D53JxEhbBZqKNFwkJLTNnBb5jHZ6a uNkHFctZ8u9RlgOHDudwJSAQ+yKiA2MVpYSE8cA1DOe3LzJJGuP8I/YY2C8u2YWcmasoxhYM+KZA V+4c2DW8RJ2zHzZX30bhXNOzwpOQt3fRPq9DSgJv5aaVXmaiI2D/DiJ/0WAk+ihgl6YgUrDW03rY 3Kk38S3SOic2TtlEmzk/Hq2GaWNujPbCAnmTcnb6JLV834jDmy3ltPtjQeq5l43YI+nFMaBGvxRp aUG4bv9wBIShpB3jA1JCSk5rLPMUtyCWoChAgzM7rJqdqxENFzO2KQEFawiK+CDQA5HCg58oGZlJ pakpFH0vDAf4Dky8Rg/L402iyw3mxHLgrVyxTVe3EEjNYom6tHXeZ6seKwQZ6oM9cBZXsmpxAxQI YI/jxHMENuY+5PXu+9YqvYFpS8Hl/mccH9qvTiWl39JBwv0FPEbT4mJzwfPXwuytXUr0K6RT96wV 2xd8zq8At+CT6bMrOyy3MB7nWx00tY+U4rLkgveVuE26eyFQskD9H/B9BmfCFOvQB/SkxsNN4Fkd vf7asgE3tsFZ7cicYZU3D3QS7YylepbjuCTbGpWgWe4khvhR9r7t1frZWXT0YnKs6OsL/1rMtBvc Y8RQeFjwlHUXaZpOukBa2d7QM8eEHkxRbMxv96VopflqebepFfY8UwmCFuDD/KBqT58obo0MJv5R 01ObPyPOHhFKCNldsKm7GOkPhtXfaDXcG55k5vAHIBXN3JShhT75+SwBGanCYTLe9EOWNQ8CVGE+ pZMAq08Ub+XWdgXJ0Z/OdX5lSESBidrZdE1W841z9+KbSYrmS7wA5IgaQV1Nc= X-QQ-XMRINFO: Mp0Kj//9VHAxr69bL5MkOOs= From: wujing To: gregkh@linuxfoundation.org, sasha.levin@linux.microsoft.com Cc: mingo@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, wujing , QiLiang Yuan Subject: [PATCH] sched/fair: Fix ksmd and kthreadd running on isolated CPU0 on arm64 systems Date: Mon, 6 Jan 2025 17:24:21 +0800 X-OQ-MSGID: <20250106092421.111988-1-realwujing@qq.com> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This bug can be reproduced on Kunpeng arm64 and Phytium arm physical machin= es, as well as in virtual machine environments, based on the linux-4.19.y stable branch: 1. Check the number of CPUs on the system: nproc --all 96 2. Add the parameter isolcpus=3D0-85 to the grub configuration, update grub, and reboot. 3. Check the ksmd process: ps aux | grep -i ksmd root 502 0.0 0.0 0 0 ? S 10:00 0:00 [ksmd] ps -o pid,psr,comm -p 502 PID PSR COMMAND 502 0 ksmd 4. Check the kthreadd process: ps aux | grep -i kthreadd root 2 0.0 0.0 0 0 ? S 10:00 0:00 [kthread= d] ps -o pid,psr,comm -p 2 PID PSR COMMAND 2 0 kthreadd From the output above, it can be seen that both ksmd and kthreadd are still running on CPU0, which is unreasonable since CPU0 has been isolated. Cc: stable@vger.kernel.org # 4.19.x Signed-off-by: wujing Signed-off-by: QiLiang Yuan --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0950cabfc1d0..454021ff70a1 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6211,7 +6211,7 @@ static int select_idle_cpu(struct task_struct *p, str= uct sched_domain *sd, int t =20 this_sd =3D rcu_dereference(*this_cpu_ptr(&sd_llc)); if (!this_sd) - return -1; + return housekeeping_any_cpu(HK_FLAG_DOMAIN); =20 /* * Due to large variance we need a large fuzz factor; hackbench in --=20 2.39.5