From mboxrd@z Thu Jan 1 00:00:00 1970 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 B8272C4332F for ; Mon, 24 Jan 2022 21:09:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376747AbiAXVJP (ORCPT ); Mon, 24 Jan 2022 16:09:15 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:57456 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1445711AbiAXVEs (ORCPT ); Mon, 24 Jan 2022 16:04:48 -0500 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 ams.source.kernel.org (Postfix) with ESMTPS id 21F5AB8123D; Mon, 24 Jan 2022 21:04:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20E8DC340EA; Mon, 24 Jan 2022 21:04:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643058284; bh=B2XzkCbD1hJiPE4C447BD00cSG+WKckSPUTUv11flOc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TlV+OK3AQtKuEjxHrjSkMzA/cvGhFvpVh626t0eOIK7rAikFAQueTt5m//8b11MQ4 hyRaZ5c2cpZSc7cBrgSaLubsVAYIIA9bDEi4TLzmvKGoRQfGE+J4MmDEKd34CNVeSX YY50MTIfpOUfrsOaublkzQaUy98wAlFyY4eRMGTA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Shevchenko , Hans de Goede , Sasha Levin Subject: [PATCH 5.16 0240/1039] platform/x86: wmi: Fix driver->notify() vs ->probe() race Date: Mon, 24 Jan 2022 19:33:49 +0100 Message-Id: <20220124184133.392081454@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184125.121143506@linuxfoundation.org> References: <20220124184125.121143506@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Hans de Goede [ Upstream commit 9918878676a5f9e99b98679f04b9e6c0f5426b0a ] The driver core sets struct device->driver before calling out to the bus' probe() method, this leaves a window where an ACPI notify may happen on the WMI object before the driver's probe() method has completed running, causing e.g. the driver's notify() callback to get called with drvdata not yet being set leading to a NULL pointer deref. At a check for this to the WMI core, ensuring that the notify() callback is not called before the driver is ready. Fixes: 1686f5444546 ("platform/x86: wmi: Incorporate acpi_install_notify_handler") Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede Link: https://lore.kernel.org/r/20211128190031.405620-2-hdegoede@redhat.com Signed-off-by: Sasha Levin --- drivers/platform/x86/wmi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c index 46178e03aecad..02aba274c4bc2 100644 --- a/drivers/platform/x86/wmi.c +++ b/drivers/platform/x86/wmi.c @@ -59,6 +59,7 @@ static_assert(__alignof__(struct guid_block) == 1); enum { /* wmi_block flags */ WMI_READ_TAKES_NO_ARGS, + WMI_PROBED, }; struct wmi_block { @@ -1008,6 +1009,7 @@ static int wmi_dev_probe(struct device *dev) } } + set_bit(WMI_PROBED, &wblock->flags); return 0; probe_misc_failure: @@ -1025,6 +1027,8 @@ static void wmi_dev_remove(struct device *dev) struct wmi_block *wblock = dev_to_wblock(dev); struct wmi_driver *wdriver = drv_to_wdrv(dev->driver); + clear_bit(WMI_PROBED, &wblock->flags); + if (wdriver->filter_callback) { misc_deregister(&wblock->char_dev); kfree(wblock->char_dev.name); @@ -1322,7 +1326,7 @@ static void acpi_wmi_notify_handler(acpi_handle handle, u32 event, return; /* If a driver is bound, then notify the driver. */ - if (wblock->dev.dev.driver) { + if (test_bit(WMI_PROBED, &wblock->flags) && wblock->dev.dev.driver) { struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver); struct acpi_buffer evdata = { ACPI_ALLOCATE_BUFFER, NULL }; acpi_status status; -- 2.34.1