From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C9DC842885D for ; Fri, 15 May 2026 09:08:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778836136; cv=none; b=FeQJWvAx1dU5E+IcfV5LUvTU5VHkZufVYCmLfHNJVMZk1uyQQy9QKn5DC6w8QrAuq27MhX4UiMoPNqm8QejhzEQS8pq8DF8AG9TzLKyUYkvTf6dh95OYiDf3qx2RGhUXdVWGSjv1bFmrp8zy9KqXKllj7LUWAc0Q3MkxlQGWG2Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778836136; c=relaxed/simple; bh=xqBvTs0vc701P/gxxl80LddgYMr+meImWyE0A5hj94I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QmJFcHDkKnA51NfjS4U9W/fExqsSojUCjQneni145DTDxw3jDuStf74rOLtkECm6GJWGI76DHf/dwoHimhpr3EAC8EFsdc7XIg4Gl7m3s4PC92B0+HNPn/22daVg51OKMUjOkxQpcZuTO1+8Boe602tQoHp4q8qlG3cc0O9Cw3A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=t7x7b7NK; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="t7x7b7NK" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A53951AC1; Fri, 15 May 2026 02:08:48 -0700 (PDT) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 27E5A3F85F; Fri, 15 May 2026 02:08:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1778836133; bh=xqBvTs0vc701P/gxxl80LddgYMr+meImWyE0A5hj94I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=t7x7b7NKffgrlsrz3nVIbwJKO3zU6rKx/f211626YFVUUZtGYFfcLth2RlYS3DvHN q+BtNoh4PJ624qjAtru4DH3r7Y1vcsdPsrZunDiSP1CsIjGTmH+Awl2vFEsC9DxjC7 v6wYBVpBxiniQBoWRlkT7CL87M6EFrLrrJZ9Dgm8= Date: Fri, 15 May 2026 10:08:50 +0100 From: Leo Yan To: Yeoreum Yun Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, suzuki.poulose@arm.com, mike.leach@arm.com, james.clark@linaro.org, alexander.shishkin@linux.intel.com, jie.gan@oss.qualcomm.com Subject: Re: [PATCH v6 08/13] coresight: etm4x: remove redundant call etm4_enable_hw() with hotplug Message-ID: <20260515090850.GI34802@e132581.arm.com> References: <20260422132203.977549-1-yeoreum.yun@arm.com> <20260422132203.977549-9-yeoreum.yun@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260422132203.977549-9-yeoreum.yun@arm.com> On Wed, Apr 22, 2026 at 02:21:58PM +0100, Yeoreum Yun wrote: [...] > + /* > + * Take the hotplug lock to prevent redundant calls to etm4_enable_hw(). > + * > + * The cpu_online_mask is set at the CPUHP_BRINGUP_CPU step. > + * In other words, if etm4_enable_sysfs() is called between > + * CPUHP_BRINGUP_CPU and CPUHP_AP_ARM_CORESIGHT_STARTING, > + * etm4_enable_hw() may be invoked in etm4_enable_sysfs_smp_call() > + * and then executed again in etm4_starting_cpu(). > + */ > + cpus_read_lock(); > ret = smp_call_function_single(drvdata->cpu, > etm4_enable_sysfs_smp_call, &arg, 1); > + cpus_read_unlock(); This will cause double deadlock with the patch: https://lore.kernel.org/linux-arm-kernel/20260511-arm_coresight_path_power_management_improvement-v12-6-1c9dcb1de8c9@arm.com/#t I think we need to drop this one. Thanks, Leo