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 E6E3837EFF4; Wed, 3 Jun 2026 17:59:02 +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=1780509544; cv=none; b=CrzGU0o3Mgjd+vRjSNcAo5FV1zJyq1oeiRMFldwMseGl+rHoq5r/2ypKtX+p3GUl61ab7L8W9pkMUxR+Tphx5hb5Ay7zYLJFlxIqtJsKTp1JZHDYz06HAX4+yfBEtBqHgehk/nbhbF7RW1Bt4DVsgE83ZZMehTvDFtag+fxSum0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780509544; c=relaxed/simple; bh=9KJ4gQQWYTIEuzRYz9lHEt5ZQ0ninLmdpdSg7g0SXSI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=leD/Ag9HZSnHvsQXJYuLK4KED+mwr1JPsZqLAFhnnUEUQxwMLoQfhG53bnrmyozBW7kCZqTX0LpxtV2kJVXHc6Mwu5jDiT6bH/yN8/g7rMJqRPaytmxBB9cElCIQ3C//SaA4Pke0e/g7ZE662fdPm9Cb8cKjlJ5nTcU8fTfha2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cfLy4gcp; 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="cfLy4gcp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5BDE1F00893; Wed, 3 Jun 2026 17:59:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780509542; bh=NRHQqYuYvhv5Bf3L2jF/Au9bIumMyOnifeYH8WZ77RE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cfLy4gcpOwrXxnPVQ48twY+uyKvkfXt7RXj1X3h8AUpB3NsjB2RXFwafaJH4ijOdG 2LJlL20lscx6aSmxNhKxdbGDujTk9dushMVThnkMCxS2uQ+NdwiSNw5BVfSBXjFj3m azQ7WRZSHhEPYvORqAyeIZKAbul3Bwm4kV6R167hBrxvvMdPk9Yw/bxxx3R7u4KMcG jiN9d0bXlcx2QqS9i7pwTqd3adJ009O2e8LQ/8pKiZltz2Ph44m7ZAb7lmlMeORWRv 1dMWq8SoE3fnhyq5n2watZJstfdSLrCWXbsZ4gxrcSIC2YGIxQxt15TMrc8g8m0kd9 xseqCO/X4UWpw== From: "Rafael J. Wysocki" To: Linux ACPI Cc: Dan Williams , LKML , Vishal Verma , Dave Jiang , nvdimm@lists.linux.dev, Alison Schofield , Xiang Chen Subject: [PATCH v2 2/4] ACPI: NFIT: core: Fix acpi_nfit_init() error cleanup Date: Wed, 03 Jun 2026 19:57:02 +0200 Message-ID: <1963615.tdWV9SEqCh@rafael.j.wysocki> Organization: Linux Kernel Development In-Reply-To: <5110904.31r3eYUQgx@rafael.j.wysocki> References: <5110904.31r3eYUQgx@rafael.j.wysocki> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="UTF-8" From: "Rafael J. Wysocki" If acpi_nfit_init() fails after adding the acpi_desc object to the acpi_descs list, that object is never removed from that list because the acpi_nfit_shutdown() devm action is not added for the NFIT device in that case. Next, the acpi_nfit_init() failure causes acpi_nfit_probe() to fail, the acpi_desc object is freed, and a dangling pointer is left behind in the acpi_descs. Any subsequent ACPI Machine Check Exception will trigger nfit_handle_mce() which iterates over acpi_descs and so a use-after-free will occur. Moreover, if acpi_nfit_probe() returns 0 after installing a notify handler for the NFIT device and without allocating the acpi_desc object and setting the NFIT device's driver data pointer, the acpi_desc object will be allocated by acpi_nfit_update_notify() and acpi_nfit_init() will be called to initialize it. Regardless of whether or not acpi_nfit_init() fails in that case, the acpi_nfit_shutdown() devm action is not added for the NFIT device and acpi_desc is never removed from the acpi_descs list. If the acpi_desc object is freed subsequently on driver removal, any subsequent ACPI MCE will lead to a use-after-free like in the previous case. To address the first issue mentioned above, make acpi_nfit_probe() call acpi_nfit_shutdown() directly on acpi_nfit_init() failures and to address the other one, add a remove callback to the driver and make it call acpi_nfit_shutdown(). Also, since it is now possible to pass NULL to acpi_nfit_shutdown() or the acpi_desc object passed to it may not have been initialized, add checks against NULL for acpi_desc and its nvdimm_bus field to that function and make acpi_nfit_unregister() clear the latter after unregistering the NVDIMM bus. Fixes: a61fe6f7902e ("nfit, tools/testing/nvdimm: unify common init for acpi_nfit_desc") Fixes: fbabd829fe76 ("acpi, nfit: fix module unload vs workqueue shutdown race") Signed-off-by: Rafael J. Wysocki Cc: All applicable --- drivers/acpi/nfit/core.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 8024cd3cad14..01c73be0bd00 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -3069,6 +3069,8 @@ static void acpi_nfit_unregister(void *data) struct acpi_nfit_desc *acpi_desc = data; nvdimm_bus_unregister(acpi_desc->nvdimm_bus); + /* The nvdimm_bus object may have been freed, so clear the pointer. */ + acpi_desc->nvdimm_bus = NULL; } int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz) @@ -3301,7 +3303,10 @@ static void acpi_nfit_notify(acpi_handle handle, u32 event, void *data) void acpi_nfit_shutdown(void *data) { struct acpi_nfit_desc *acpi_desc = data; - struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus); + struct device *bus_dev; + + if (!acpi_desc || !acpi_desc->nvdimm_bus) + return; /* * Destruct under acpi_desc_lock so that nfit_handle_mce does not @@ -3316,6 +3321,7 @@ void acpi_nfit_shutdown(void *data) mutex_unlock(&acpi_desc->init_mutex); cancel_delayed_work_sync(&acpi_desc->dwork); + bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus); /* * Bounce the nvdimm bus lock to make sure any in-flight * acpi_nfit_ars_rescan() submissions have had a chance to @@ -3388,9 +3394,14 @@ static int acpi_nfit_probe(struct platform_device *pdev) sz - sizeof(struct acpi_table_nfit)); if (rc) - return rc; + acpi_nfit_shutdown(acpi_desc); - return devm_add_action_or_reset(dev, acpi_nfit_shutdown, acpi_desc); + return rc; +} + +static void acpi_nfit_remove(struct platform_device *pdev) +{ + acpi_nfit_shutdown(platform_get_drvdata(pdev)); } static void acpi_nfit_update_notify(struct device *dev, acpi_handle handle) @@ -3474,6 +3485,7 @@ MODULE_DEVICE_TABLE(acpi, acpi_nfit_ids); static struct platform_driver acpi_nfit_driver = { .probe = acpi_nfit_probe, + .remove = acpi_nfit_remove, .driver = { .name = "acpi-nfit", .acpi_match_table = acpi_nfit_ids, -- 2.51.0