From nobody Mon Dec 15 18:29:28 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7FD4EC38A2D for ; Mon, 24 Oct 2022 19:24:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231415AbiJXTYs (ORCPT ); Mon, 24 Oct 2022 15:24:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232105AbiJXTWs (ORCPT ); Mon, 24 Oct 2022 15:22:48 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD6A8C4DA1; Mon, 24 Oct 2022 10:57:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 535D7CE134D; Mon, 24 Oct 2022 11:52:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67333C433D6; Mon, 24 Oct 2022 11:52:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666612352; bh=QsAUGu98aFCufOBe4iBWZ+qBocl7d9WXykBVUjlzfZ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UvlB8XkOxmPArORef54xfQrXmn/wGt4pRGP9jYk4SckPA2m8Bquv02bIXXDtNc4Py ddNP+DMwy4BVCzV9wD2sE2VDXxwX7QnKX8Chihi0H38PwO2dyHPc1Np5PdeMcihapP rzj/ix0nJVYQpGhcACL3RLu7dc2OmmS50lUd+2S0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chen Yu , Srinivas Pandruvada , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 4.14 164/210] thermal: intel_powerclamp: Use get_cpu() instead of smp_processor_id() to avoid crash Date: Mon, 24 Oct 2022 13:31:21 +0200 Message-Id: <20221024113002.289703206@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112956.797777597@linuxfoundation.org> References: <20221024112956.797777597@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Srinivas Pandruvada [ Upstream commit 68b99e94a4a2db6ba9b31fe0485e057b9354a640 ] When CPU 0 is offline and intel_powerclamp is used to inject idle, it generates kernel BUG: BUG: using smp_processor_id() in preemptible [00000000] code: bash/15687 caller is debug_smp_processor_id+0x17/0x20 CPU: 4 PID: 15687 Comm: bash Not tainted 5.19.0-rc7+ #57 Call Trace: dump_stack_lvl+0x49/0x63 dump_stack+0x10/0x16 check_preemption_disabled+0xdd/0xe0 debug_smp_processor_id+0x17/0x20 powerclamp_set_cur_state+0x7f/0xf9 [intel_powerclamp] ... ... Here CPU 0 is the control CPU by default and changed to the current CPU, if CPU 0 offlined. This check has to be performed under cpus_read_lock(), hence the above warning. Use get_cpu() instead of smp_processor_id() to avoid this BUG. Suggested-by: Chen Yu Signed-off-by: Srinivas Pandruvada [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/thermal/intel_powerclamp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/thermal/intel_powerclamp.c b/drivers/thermal/intel_pow= erclamp.c index c3293fa2bb1b..7ff59f86a543 100644 --- a/drivers/thermal/intel_powerclamp.c +++ b/drivers/thermal/intel_powerclamp.c @@ -550,8 +550,10 @@ static int start_power_clamp(void) =20 /* prefer BSP */ control_cpu =3D 0; - if (!cpu_online(control_cpu)) - control_cpu =3D smp_processor_id(); + if (!cpu_online(control_cpu)) { + control_cpu =3D get_cpu(); + put_cpu(); + } =20 clamping =3D true; schedule_delayed_work(&poll_pkg_cstate_work, 0); --=20 2.35.1