From nobody Tue Apr 7 12:46:18 2026 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 9855CC4332F for ; Fri, 11 Nov 2022 01:57:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232653AbiKKB5E (ORCPT ); Thu, 10 Nov 2022 20:57:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232714AbiKKB4l (ORCPT ); Thu, 10 Nov 2022 20:56:41 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6EAB858003 for ; Thu, 10 Nov 2022 17:56:40 -0800 (PST) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4N7hYN4MFGzqSGq; Fri, 11 Nov 2022 09:52:56 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 11 Nov 2022 09:56:38 +0800 Received: from ubuntu1804.huawei.com (10.67.175.36) by dggpemm500013.china.huawei.com (7.185.36.172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 11 Nov 2022 09:56:38 +0800 From: Chen Zhongjin To: CC: , , Subject: [PATCH v2] firmware: dmi-sysfs: Fix null-ptr-deref in dmi_sysfs_register_handle Date: Fri, 11 Nov 2022 09:53:26 +0800 Message-ID: <20221111015326.251650-2-chenzhongjin@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20221111015326.251650-1-chenzhongjin@huawei.com> References: <20221111015326.251650-1-chenzhongjin@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.175.36] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500013.china.huawei.com (7.185.36.172) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" KASAN reported a null-ptr-deref error: KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 1373 Comm: modprobe Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:dmi_sysfs_entry_release ... Call Trace: kobject_put dmi_sysfs_register_handle (drivers/firmware/dmi-sysfs.c:540) dmi_sysfs dmi_decode_table (drivers/firmware/dmi_scan.c:133) dmi_walk (drivers/firmware/dmi_scan.c:1115) dmi_sysfs_init (drivers/firmware/dmi-sysfs.c:149) dmi_sysfs do_one_initcall (init/main.c:1296) ... Kernel panic - not syncing: Fatal exception Kernel Offset: 0x4000000 from 0xffffffff81000000 ---[ end Kernel panic - not syncing: Fatal exception ]--- It is because previous patch added kobject_put() to release the memory which will call dmi_sysfs_entry_release() and list_del(). However, list_add_tail(entry->list) is called after the error block, so the list_head is uninitialized and cannot be deleted. Move error handling to after list_add_tail to fix this. Fixes: 660ba678f999 ("firmware: dmi-sysfs: Fix memory leak in dmi_sysfs_reg= ister_handle") Signed-off-by: Chen Zhongjin --- v1 -> v2: Change fix to moving error handling to after list_add_tail. So that it is consistent with kobject_put(&entry->kobj) in other places. --- drivers/firmware/dmi-sysfs.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c index 66727ad3361b..402217c57033 100644 --- a/drivers/firmware/dmi-sysfs.c +++ b/drivers/firmware/dmi-sysfs.c @@ -603,16 +603,16 @@ static void __init dmi_sysfs_register_handle(const st= ruct dmi_header *dh, *ret =3D kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL, "%d-%d", dh->type, entry->instance); =20 - if (*ret) { - kobject_put(&entry->kobj); - return; - } - /* Thread on the global list for cleanup */ spin_lock(&entry_list_lock); list_add_tail(&entry->list, &entry_list); spin_unlock(&entry_list_lock); =20 + if (*ret) { + kobject_put(&entry->kobj); + return; + } + /* Handle specializations by type */ switch (dh->type) { case DMI_ENTRY_SYSTEM_EVENT_LOG: --=20 2.17.1