From patchwork Tue May 15 23:57:23 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shuah X-Patchwork-Id: 10402339 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 26E27600F4 for ; Tue, 15 May 2018 23:58:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 122C31FE82 for ; Tue, 15 May 2018 23:58:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 068F91FF29; Tue, 15 May 2018 23:58:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A41121FE82 for ; Tue, 15 May 2018 23:58:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752674AbeEOX5y (ORCPT ); Tue, 15 May 2018 19:57:54 -0400 Received: from mailout.easymail.ca ([64.68.200.34]:55294 "EHLO mailout.easymail.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751402AbeEOX5v (ORCPT ); Tue, 15 May 2018 19:57:51 -0400 Received: from localhost (localhost [127.0.0.1]) by mailout.easymail.ca (Postfix) with ESMTP id C5F5741AD2; Tue, 15 May 2018 23:57:50 +0000 (UTC) Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (emo03-pco.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id sJBOt9yl36_I; Tue, 15 May 2018 23:57:50 +0000 (UTC) Received: from localhost.localdomain (c-24-9-64-241.hsd1.co.comcast.net [24.9.64.241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mailout.easymail.ca (Postfix) with ESMTPSA id DC84E41830; Tue, 15 May 2018 23:57:44 +0000 (UTC) From: "Shuah Khan (Samsung OSG)" To: valentina.manea.m@gmail.com, shuah@kernel.org, gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] usbip: usbip_host: fix bad unlock balance during stub_probe() Date: Tue, 15 May 2018 17:57:23 -0600 Message-Id: <20180515235723.30845-1-shuah@kernel.org> X-Mailer: git-send-email 2.14.1 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP stub_probe() calls put_busid_priv() in an error path when device isn't found in the busid_table. Fix it by making put_busid_priv() safe to be called with null struct bus_id_priv pointer. This problem happens when "usbip bind" is run without loading usbip_host driver and then running modprobe. The first failed bind attempt unbinds the device from the original driver and when usbip_host is modprobed, stub_probe() runs and doesn't find the device in its busid table and calls put_busid_priv(0 with null bus_id_priv pointer. usbip-host 3-10.2: 3-10.2 is not in match_busid table... skip! [ 367.359679] ===================================== [ 367.359681] WARNING: bad unlock balance detected! [ 367.359683] 4.17.0-rc4+ #5 Not tainted [ 367.359685] ------------------------------------- [ 367.359688] modprobe/2768 is trying to release lock ( [ 367.359689] ================================================================== [ 367.359696] BUG: KASAN: null-ptr-deref in print_unlock_imbalance_bug+0x99/0x110 [ 367.359699] Read of size 8 at addr 0000000000000058 by task modprobe/2768 [ 367.359705] CPU: 4 PID: 2768 Comm: modprobe Not tainted 4.17.0-rc4+ #5 Fixes: 22076557b07c ("usbip: usbip_host: fix NULL-ptr deref and use-after-free errors") in usb-linus Signed-off-by: Shuah Khan (Samsung OSG) --- drivers/usb/usbip/stub_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c index 41c7b9de2a92..bf8a5feb0ee9 100644 --- a/drivers/usb/usbip/stub_main.c +++ b/drivers/usb/usbip/stub_main.c @@ -82,7 +82,8 @@ struct bus_id_priv *get_busid_priv(const char *busid) void put_busid_priv(struct bus_id_priv *bid) { - spin_unlock(&bid->busid_lock); + if (bid) + spin_unlock(&bid->busid_lock); } static int add_match_busid(char *busid)