From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D0D8D2EE262; Tue, 31 Mar 2026 16:27:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774974451; cv=none; b=JCN4LP0vH+AW+6T64/1SDp/+cf80e7cSMjvPUwN0vBZxO53f/rAb3mX09KhTrUaBY8hzqzh2zGngySbvIXHLf1iLEeqUFN/47P6yBlsGSVHAnfXYjk2lo70Tkrwmp+hvBLbFQVeR9nXQNh0GRKBJ4QVN+BnQf9svAJMj673vixQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774974451; c=relaxed/simple; bh=AzUSUHxLpBwcGg91HDZgbxC0ozwg9lXWD9Y07c8D2Gs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t6NNjbmTsr9/SPxutO76IMrozA93O5oW1t4RPcp/VDixyBjNHqDU0l+NxJSKtpRstUJJl7WeLHcARMC/Ee1fowuoY5W1AOX0canqvOnvLgyxlKsp/A/75evsGutNhnwxXNjy8ohxxhNyyvHUZ3xf2ATDruH8RqMxk3w+AQL6Njs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sEig3Njl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="sEig3Njl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66737C19423; Tue, 31 Mar 2026 16:27:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774974451; bh=AzUSUHxLpBwcGg91HDZgbxC0ozwg9lXWD9Y07c8D2Gs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sEig3Njlo0UdxEUVBPP/2iEj44g0XPB+ojyy568g5xfDOARV1w4Z04YBjXU+th6eY 0GAa2Ri0sucEe2d6uob72Y9z3wQ0R/NIdC38wRlmn3cHogMLVBdrxk8PTNZ48Vd2pe BtXSG/bqkael0Wbd5ioNn8OLh89eDpJtXKTqlW8g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Weiming Shi , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 6.6 091/175] ACPI: EC: clean up handlers on probe failure in acpi_ec_setup() Date: Tue, 31 Mar 2026 18:21:15 +0200 Message-ID: <20260331161733.113663255@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161729.779738837@linuxfoundation.org> References: <20260331161729.779738837@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Weiming Shi [ Upstream commit f6484cadbcaf26b5844b51bd7307a663dda48ef6 ] When ec_install_handlers() returns -EPROBE_DEFER on reduced-hardware platforms, it has already started the EC and installed the address space handler with the struct acpi_ec pointer as handler context. However, acpi_ec_setup() propagates the error without any cleanup. The caller acpi_ec_add() then frees the struct acpi_ec for non-boot instances, leaving a dangling handler context in ACPICA. Any subsequent AML evaluation that accesses an EC OpRegion field dispatches into acpi_ec_space_handler() with the freed pointer, causing a use-after-free: BUG: KASAN: slab-use-after-free in mutex_lock (kernel/locking/mutex.c:289) Write of size 8 at addr ffff88800721de38 by task init/1 Call Trace: mutex_lock (kernel/locking/mutex.c:289) acpi_ec_space_handler (drivers/acpi/ec.c:1362) acpi_ev_address_space_dispatch (drivers/acpi/acpica/evregion.c:293) acpi_ex_access_region (drivers/acpi/acpica/exfldio.c:246) acpi_ex_field_datum_io (drivers/acpi/acpica/exfldio.c:509) acpi_ex_extract_from_field (drivers/acpi/acpica/exfldio.c:700) acpi_ex_read_data_from_field (drivers/acpi/acpica/exfield.c:327) acpi_ex_resolve_node_to_value (drivers/acpi/acpica/exresolv.c:392) Allocated by task 1: acpi_ec_alloc (drivers/acpi/ec.c:1424) acpi_ec_add (drivers/acpi/ec.c:1692) Freed by task 1: kfree (mm/slub.c:6876) acpi_ec_add (drivers/acpi/ec.c:1751) The bug triggers on reduced-hardware EC platforms (ec->gpe < 0) when the GPIO IRQ provider defers probing. Once the stale handler exists, any unprivileged sysfs read that causes AML to touch an EC OpRegion (battery, thermal, backlight) exercises the dangling pointer. Fix this by calling ec_remove_handlers() in the error path of acpi_ec_setup() before clearing first_ec. ec_remove_handlers() checks each EC_FLAGS_* bit before acting, so it is safe to call regardless of how far ec_install_handlers() progressed: -ENODEV (handler not installed): only calls acpi_ec_stop() -EPROBE_DEFER (handler installed): removes handler, stops EC Fixes: 03e9a0e05739 ("ACPI: EC: Consolidate event handler installation code") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Link: https://patch.msgid.link/20260324165458.1337233-2-bestswngs@gmail.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/ec.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 8e304efde3429..f94cddbbb55ac 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -1653,6 +1653,8 @@ static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool ca ret = ec_install_handlers(ec, device, call_reg); if (ret) { + ec_remove_handlers(ec); + if (ec == first_ec) first_ec = NULL; -- 2.53.0