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=-14.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 F0BBDC43466 for ; Mon, 21 Sep 2020 14:42:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDE432311D for ; Mon, 21 Sep 2020 14:42:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699371; bh=c+BtdsoEL/TbNxvyh/KaWEjduuXtxTnCLoMjV2rtJOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pqN6cC5YcOXEFJmd6wiLkhh0I19dtiJ/lLust2Prymz7ZWkdNUpTcj54v4kQ22KpY VlZHXHfV4FkP2oYE8zqSs3QcDv98Sfrr9ZQYmDrxj03IVac2hJHRFVsvbzMoCOfN13 f6Pe72rZHLkWHwDC9P0+6D1TL9EzRqM0s5XwkeJM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728193AbgIUOmu (ORCPT ); Mon, 21 Sep 2020 10:42:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:49882 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727804AbgIUOlL (ORCPT ); Mon, 21 Sep 2020 10:41:11 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EF747238A1; Mon, 21 Sep 2020 14:41:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699267; bh=c+BtdsoEL/TbNxvyh/KaWEjduuXtxTnCLoMjV2rtJOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0UpzQymXRpY1wz7LzzCAKQIEZHb/l1n/bsPeLUQ3T2Dt/WMVGgnYlb+I0rxxe6vfl hvlK/d7L07S2hByUryDp204iWKbDhAb3FFA1EHN0LSxXXthtFJYCF0Gg1W7sk5FEEr wUq01e49EywoHJ9nMYrX9SeCBZU97J2wdYwpVjKM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Borislav Petkov , Sasha Levin , linux-edac@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 10/15] EDAC/ghes: Check whether the driver is on the safe list correctly Date: Mon, 21 Sep 2020 10:40:49 -0400 Message-Id: <20200921144054.2135602-10-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200921144054.2135602-1-sashal@kernel.org> References: <20200921144054.2135602-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov [ Upstream commit 251c54ea26fa6029b01a76161a37a12fde5124e4 ] With CONFIG_DEBUG_TEST_DRIVER_REMOVE=y, a system would try to probe, unregister and probe again a driver. When ghes_edac is attempted to be loaded on a system which is not on the safe platforms list, ghes_edac_register() would return early. The unregister counterpart ghes_edac_unregister() would still attempt to unregister and exit early at the refcount test, leading to the refcount underflow below. In order to not do *anything* on the unregister path too, reuse the force_load parameter and check it on that path too, before fumbling with the refcount. ghes_edac: ghes_edac_register: entry ghes_edac: ghes_edac_register: return -ENODEV ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 10 PID: 1 at lib/refcount.c:28 refcount_warn_saturate+0xb9/0x100 Modules linked in: CPU: 10 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc4+ #12 Hardware name: GIGABYTE MZ01-CE1-00/MZ01-CE1-00, BIOS F02 08/29/2018 RIP: 0010:refcount_warn_saturate+0xb9/0x100 Code: 82 e8 fb 8f 4d 00 90 0f 0b 90 90 c3 80 3d 55 4c f5 00 00 75 88 c6 05 4c 4c f5 00 01 90 48 c7 c7 d0 8a 10 82 e8 d8 8f 4d 00 90 <0f> 0b 90 90 c3 80 3d 30 4c f5 00 00 0f 85 61 ff ff ff c6 05 23 4c RSP: 0018:ffffc90000037d58 EFLAGS: 00010292 RAX: 0000000000000026 RBX: ffff88840b8da000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffff8216b24f RDI: 00000000ffffffff RBP: ffff88840c662e00 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000046 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88840ee80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000800002211000 CR4: 00000000003506e0 Call Trace: ghes_edac_unregister ghes_remove platform_drv_remove really_probe driver_probe_device device_driver_attach __driver_attach ? device_driver_attach ? device_driver_attach bus_for_each_dev bus_add_driver driver_register ? bert_init ghes_init do_one_initcall ? rcu_read_lock_sched_held kernel_init_freeable ? rest_init kernel_init ret_from_fork ... ghes_edac: ghes_edac_unregister: FALSE, refcount: -1073741824 Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200911164950.GB19320@zn.tnic Signed-off-by: Sasha Levin --- drivers/edac/ghes_edac.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c index 523dd56a798c9..0031819402d0c 100644 --- a/drivers/edac/ghes_edac.c +++ b/drivers/edac/ghes_edac.c @@ -488,6 +488,7 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev) if (!force_load && idx < 0) return -ENODEV; } else { + force_load = true; idx = 0; } @@ -586,6 +587,9 @@ void ghes_edac_unregister(struct ghes *ghes) struct mem_ctl_info *mci; unsigned long flags; + if (!force_load) + return; + mutex_lock(&ghes_reg_mutex); if (!refcount_dec_and_test(&ghes_refcount)) -- 2.25.1