From patchwork Thu Oct 27 12:13:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Zhongjin X-Patchwork-Id: 619923 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 3B166ECAAA1 for ; Thu, 27 Oct 2022 12:17:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234722AbiJ0MRW (ORCPT ); Thu, 27 Oct 2022 08:17:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234375AbiJ0MRS (ORCPT ); Thu, 27 Oct 2022 08:17:18 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02B0C9FFC; Thu, 27 Oct 2022 05:17:17 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Myl2g4VQ3zpW3F; Thu, 27 Oct 2022 20:13:47 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 27 Oct 2022 20:17:14 +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; Thu, 27 Oct 2022 20:17:14 +0800 From: Chen Zhongjin To: , CC: , , Subject: [PATCH v2] i2c: piix4: Fix adapter not be removed in piix4_remove() Date: Thu, 27 Oct 2022 20:13:53 +0800 Message-ID: <20221027121353.181695-1-chenzhongjin@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.67.175.36] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500013.china.huawei.com (7.185.36.172) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org In piix4_probe(), the piix4 adapter will be registered in: piix4_probe() piix4_add_adapters_sb800() / piix4_add_adapter() i2c_add_adapter() Based on the probed device type, piix4_add_adapters_sb800() or single piix4_add_adapter() will be called. For the former case, piix4_adapter_count is set as the number of adapters, while for antoher case it is not set and kept default *zero*. When piix4 is removed, piix4_remove() removes the adapters added in piix4_probe(), basing on the piix4_adapter_count value. Because the count is zero for the single adapter case, the adapter won't be removed and makes the sources allocated for adapter leaked, such as the i2c client and device. These sources can still be accessed by i2c or bus and cause problems. An easily reproduced case is that if a new adapter is registered, i2c will get the leaked adapter and try to call smbus_algorithm, which was already freed: Triggered by: rmmod i2c_piix4 && modprobe max31730 BUG: unable to handle page fault for address: ffffffffc053d860 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3752 Comm: modprobe Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:i2c_default_probe (drivers/i2c/i2c-core-base.c:2259) i2c_core RSP: 0018:ffff888107477710 EFLAGS: 00000246 ... i2c_detect (drivers/i2c/i2c-core-base.c:2302) i2c_core __process_new_driver (drivers/i2c/i2c-core-base.c:1336) i2c_core bus_for_each_dev (drivers/base/bus.c:301) i2c_for_each_dev (drivers/i2c/i2c-core-base.c:1823) i2c_core i2c_register_driver (drivers/i2c/i2c-core-base.c:1861) i2c_core do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... ---[ end trace 0000000000000000 ]--- Fix this problem by correctly set piix4_adapter_count as 1 for the single adapter so it can be normally removed. Fixes: 528d53a1592b ("i2c: piix4: Fix probing of reserved ports on AMD Family 16h Model 30h") Signed-off-by: Chen Zhongjin --- v1 -> v2: Set piix4_adapter_count as 1 rather than increase it and slightly fix the commit message. --- drivers/i2c/busses/i2c-piix4.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c index 39cb1b7bb865..809fbd014cd6 100644 --- a/drivers/i2c/busses/i2c-piix4.c +++ b/drivers/i2c/busses/i2c-piix4.c @@ -1080,6 +1080,7 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id) "", &piix4_main_adapters[0]); if (retval < 0) return retval; + piix4_adapter_count = 1; } /* Check for auxiliary SMBus on some AMD chipsets */