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 X-Spam-Level: X-Spam-Status: No, score=-19.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 997E3C432BE for ; Mon, 26 Jul 2021 16:32:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82CBE60F5E for ; Mon, 26 Jul 2021 16:32:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238787AbhGZPvi (ORCPT ); Mon, 26 Jul 2021 11:51:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:46900 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232878AbhGZPaz (ORCPT ); Mon, 26 Jul 2021 11:30:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 342776056B; Mon, 26 Jul 2021 16:11:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627315883; bh=uPoPKBsjhLxRzU4uNbpppdSV3AAGDMad4RgMyiDG+bc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eFshEhb+6Bx16L1Gk0z7S08IM1jpB5uQt/B9dH5EP1gYb547D0AvT3gTvkAIy0sTY J0fYGsvG4nYr5jlWhrkHTTT7Zf2mp+Gni//JRbhvv71f7fUWC/PjGUBMpV/+kQzQcj CQdbeBqqSQdh3xV15/GfcsKnxYfsorC9tmKUQpmc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Shevchenko , Daniel Scally , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 5.13 103/223] ACPI: utils: Fix reference counting in for_each_acpi_dev_match() Date: Mon, 26 Jul 2021 17:38:15 +0200 Message-Id: <20210726153849.647960503@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210726153846.245305071@linuxfoundation.org> References: <20210726153846.245305071@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: linux-kernel@vger.kernel.org From: Andy Shevchenko [ Upstream commit 71f6428332844f38c7cb10461d9f29e9c9b983a0 ] Currently it's possible to iterate over the dangling pointer in case the device suddenly disappears. This may happen becase callers put it at the end of a loop. Instead, let's move that call inside acpi_dev_get_next_match_dev(). Fixes: 803abec64ef9 ("media: ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver") Fixes: bf263f64e804 ("media: ACPI / bus: Add acpi_dev_get_next_match_dev() and helper macro") Fixes: edbd1bc4951e ("efi/dev-path-parser: Switch to use for_each_acpi_dev_match()") Signed-off-by: Andy Shevchenko Reviewed-by: Daniel Scally Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/utils.c | 7 +++---- drivers/firmware/efi/dev-path-parser.c | 1 - drivers/media/pci/intel/ipu3/cio2-bridge.c | 6 ++---- include/acpi/acpi_bus.h | 5 ----- 4 files changed, 5 insertions(+), 14 deletions(-) diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c index 3b54b8fd7396..27ec9d57f3b8 100644 --- a/drivers/acpi/utils.c +++ b/drivers/acpi/utils.c @@ -846,11 +846,9 @@ EXPORT_SYMBOL(acpi_dev_present); * Return the next match of ACPI device if another matching device was present * at the moment of invocation, or NULL otherwise. * - * FIXME: The function does not tolerate the sudden disappearance of @adev, e.g. - * in the case of a hotplug event. That said, the caller should ensure that - * this will never happen. - * * The caller is responsible for invoking acpi_dev_put() on the returned device. + * On the other hand the function invokes acpi_dev_put() on the given @adev + * assuming that its reference counter had been increased beforehand. * * See additional information in acpi_dev_present() as well. */ @@ -866,6 +864,7 @@ acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const cha match.hrv = hrv; dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb); + acpi_dev_put(adev); return dev ? to_acpi_device(dev) : NULL; } EXPORT_SYMBOL(acpi_dev_get_next_match_dev); diff --git a/drivers/firmware/efi/dev-path-parser.c b/drivers/firmware/efi/dev-path-parser.c index 10d4457417a4..eb9c65f97841 100644 --- a/drivers/firmware/efi/dev-path-parser.c +++ b/drivers/firmware/efi/dev-path-parser.c @@ -34,7 +34,6 @@ static long __init parse_acpi_path(const struct efi_dev_path *node, break; if (!adev->pnp.unique_id && node->acpi.uid == 0) break; - acpi_dev_put(adev); } if (!adev) return -ENODEV; diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.c b/drivers/media/pci/intel/ipu3/cio2-bridge.c index 4657e99df033..59a36f922675 100644 --- a/drivers/media/pci/intel/ipu3/cio2-bridge.c +++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c @@ -173,10 +173,8 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg, int ret; for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) { - if (!adev->status.enabled) { - acpi_dev_put(adev); + if (!adev->status.enabled) continue; - } if (bridge->n_sensors >= CIO2_NUM_PORTS) { acpi_dev_put(adev); @@ -185,7 +183,6 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg, } sensor = &bridge->sensors[bridge->n_sensors]; - sensor->adev = adev; strscpy(sensor->name, cfg->hid, sizeof(sensor->name)); ret = cio2_bridge_read_acpi_buffer(adev, "SSDB", @@ -215,6 +212,7 @@ static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg, goto err_free_swnodes; } + sensor->adev = acpi_dev_get(adev); adev->fwnode.secondary = fwnode; dev_info(&cio2->dev, "Found supported sensor %s\n", diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index 3a82faac5767..bff6a11bb21f 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -698,11 +698,6 @@ acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv); * @hrv: Hardware Revision of the device, pass -1 to not check _HRV * * The caller is responsible for invoking acpi_dev_put() on the returned device. - * - * FIXME: Due to above requirement there is a window that may invalidate @adev - * and next iteration will use a dangling pointer, e.g. in the case of a - * hotplug event. That said, the caller should ensure that this will never - * happen. */ #define for_each_acpi_dev_match(adev, hid, uid, hrv) \ for (adev = acpi_dev_get_first_match_dev(hid, uid, hrv); \ -- 2.30.2