From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 24CA24A8A09; Thu, 3 Sep 2026 12:40:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788439257; cv=none; b=KKnNlMReRycMPSpqW4hjmTENG2U4T9EFmrnb1ZCiq1gwXkjhrpYdG1PR0to5TDETK9pVAQZElZ+0p7UFgbkenoZKgcNANKp/YvbuagY/wXI/0j00kLicjIOK8aT8nMg/SZErhc4c5d9jpBHIRiepuLyI5MBlMjvage4+XIRXuh4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788439257; c=relaxed/simple; bh=ZD3dQyJAxu0TJMKJm0s6MCvTM1Nx9fBW+1vG9yorNtg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=K/9z44qyvsGJ05qE7/JiccF6coC41jBfDp4aWV7Oey0voBiOcPMCZmvQgNVrz+XiBKFDISfpFsb9uRz7mjB9++UZLaDmBvZ+lDcPBGX5iKAaglByUxeWnjnCOIrnkcAnjEaa85/+jUaO92Nzz5AiXyghm1imgBfYz11X73LS60A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KDDMp1wB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KDDMp1wB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93EF41F00ADB; Thu, 3 Sep 2026 12:40:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788439255; bh=wdl9ZnhdN69qpVgnEuB/oxRMf60WEpbQOzfRFr3d1qQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=KDDMp1wBSOf9oB65PQQ1G0XijtsiUucEA9i0BzkxagOXeLVIrRhG4gY07keWEibSQ UvA1/0xBmdHQAsWmMBMccq81Cz66WUgfDjdlxCB2WN/ADRrm4BOzIJBu6/aCNCz3Zh oTtqxNqpmr7j6OgGX7S+c2TAZWIfHGqL7t1KeATtKoVdje2jiSMeyWFIrA6ifiCsMa qQLoGWH2vKDYANtE9+db8sIL2HLS/XNrFt+PriR6ho5g7P8HzktH4B7jZqcQub14hI pgI+wx2I4d3Y92zrv6NEpQa0sGmqlDDw/lZ29p2svZrPiLyCTdNtU1wVnMP1bNUZur 7Vu+uiGN82yLQ== Date: Thu, 3 Sep 2026 13:40:52 +0100 From: Sudeep Holla To: Christian Loehle Cc: Jassi Brar , breno Leitao , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 2/2] mailbox: pcc: Serialize channel updates with shared memory teardown Message-ID: <20260903-solid-unbiased-hog-26c0ef@sudeepholla> References: <20260903111328.805352-1-christian.loehle@arm.com> <20260903111328.805352-3-christian.loehle@arm.com> Precedence: bulk X-Mailing-List: linux-acpi@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: <20260903111328.805352-3-christian.loehle@arm.com> On Thu, Sep 03, 2026 at 12:13:28PM +0100, Christian Loehle wrote: > mbox_free_channel() makes a PCC channel available before the subsequent > shared-memory unmap. Without serialization, a concurrent request can bind a > new client and replace the mapping, which the old release then unmaps. > > Serialize PCC channel acquisition and release. Keep the channel unavailable > until the old shared-memory mapping has been removed. > > Suggested-by: Sudeep Holla Reviewed-by: Sudeep Holla -- Regards, Sudeep