From nobody Tue Feb 10 17:08:08 2026 Received: from out203-205-221-239.mail.qq.com (out203-205-221-239.mail.qq.com [203.205.221.239]) (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 85AA31C5F21; Mon, 6 Jan 2025 09:04:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.205.221.239 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736154258; cv=none; b=VK268m/Fs98C/3vyU9PHCucFRqfop0AZPFvXiqpKfxVXsqi5tE4sO/4SZ4h1qhYIqzvenSNVLy4qr7Bl8u6jcMBrBi9sQ5mWQAAksObTZx6Yg3awLClnzmBkVn+BTKc1PNi9IUdMZIlIsLkP/6otivcZFxOlaTvwl4fvH25frRU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736154258; c=relaxed/simple; bh=Fwda7ENx6jfw7Tv5idKqtnAlSTwBTZLMw4Fp/soVc+k=; h=Message-ID:From:To:Cc:Subject:Date:MIME-Version; b=fh8zx/y8QX0zJVzw7YwMfxeNLpAgwQNY/baUQnGj/v4aHz4AAdpEgfmQ31F3EZPN4MHlkO+sSVk1S8BP36kLxHvOJosIGmfLdwtlaAcFrhwgufqWU2pdCt0QAqOt0XEq/jSrYHHpP12CB6ayPHj8jhLx2HY8nvBgzwcRXYelRaE= 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=fCLJmzAV; arc=none smtp.client-ip=203.205.221.239 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="fCLJmzAV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1736154247; bh=+340KkDQwCYYi+sjsr57zo5fiNS8/fmuOnbgQDlfNvU=; h=From:To:Cc:Subject:Date; b=fCLJmzAVMw9osaFzU5qHR6CThtktxGGbFuRKFMr5Wt3aGAtnqsVelsEDYU/d8dzhB cSxPv0k+MWgbDE5J9SLggtVWxJ3JkkjhTEDK1M2nu1OWXgsSjdTurheZp5H6akeYRw un1uqgt5y0fuDHkfifZXRHC8Nz7HeYv8OVQVuAYY= Received: from localhost.localdomain ([101.227.46.164]) by newxmesmtplogicsvrszc25-0.qq.com (NewEsmtp) with SMTP id 10525C45; Mon, 06 Jan 2025 17:04:05 +0800 X-QQ-mid: xmsmtpt1736154245tsquxuqxm Message-ID: X-QQ-XMAILINFO: MTEKjEyAppcsDb0OiELRUSiBbE5BpZjZAZaShOeukoqvwhDJ3IprKeths7UWfz PRJ1DDVYSygIQzxOR7VvEVIMJPVBP10joay4UTJQMLuLGUxCTS1NUeYYA3C6g83MfYRkaa2AWe/r HVdgFKTwKOqB8IbW4K9r/svKIF7BAaQCeVqneFhR82z8e52mXHZ1T8AGwSXIR1NWvCBOV/787HbU p1Ts9qlHUpyvY01XezekdSKKwZrkynnIBK6Lz3DOcBxEYqI6AUSguLjG5bFHsrrGM+iPC9L7B8Nz NEiqx4tNSZQiq2XT6iXfS/9vjirST3CPWvpXg7BgRKT9H9mZY+l3CvFbAazq0JS56b2cjveOHkHf z+V+xpeTTVTEigrLDy9Y2d5K0CWn6TIxybzrdR8F20Oiou5RPUpeUNpr8b8wZBJyapH65z4sNXAh 0BMityR3tpBi/+uOodojFDgU35rJCxgFKWrH3zI9ba/A8YJBLBzKyiEHh8mJW3jWkzCC/n42VnfU js6undVcPVUL9II+eYX/BdgcPpa1ntUrxEIaO+QWOIo0w1cxr9iFbZZR73gk5KeMW4m1Q2Ubv5/X YWa3Rr72dwdIWhpJVQpRySQPoyydwS9nYrE2/0TxBDRCGc2qCgqsF2MvuYOrYQRP5tbn8woaD/Zf 3TZ3JUunCAJ2H03BKUNXpa/Yl3ItnAFlW/r28abUAKCsK0hMO7WjMPoR+dtMtPgwWSjsU9WO8l8J mFGZQ/fOWZPmT/fsFJsjd06UJOSwUN01hX5eTHStwwMU49yRbBrf4RDaEsnuWyUZOMiKyYV2JW8Q xJW37lGOQczFgqTafKqT1dKzBA+ALdk/tYsy9MkXRF6mM0F6e1oyMF9d8MFMBp8flsjMRUABL9TO KqIc2o9GRM6GIHYSiVdu1MeqXkfkWtQX8BuXL5h/thY1I/UOxenTcRAwcftCLGZ8ypCnxe2xuCVA vMCZ1HhUYa1FWUqC7/k4fvabyQHxc16R2OtIvgJ2ebS3uN9DDswGa25J2IJE42gOo2W+b636NilN aLSr6p9Kel3a7/6plHn84JJ3S7fZgOEqdStcWtX0QMDLUQ00caE/oxXIDb2GI= X-QQ-XMRINFO: NS+P29fieYNw95Bth2bWPxk= 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 17:04:03 +0800 X-OQ-MSGID: <20250106090403.102026-1-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. 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