From patchwork Thu Mar 4 15:24:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 12116493 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 BE3ACC4321A for ; Thu, 4 Mar 2021 15:27:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FC3B64FAF for ; Thu, 4 Mar 2021 15:27:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234807AbhCDP0s (ORCPT ); Thu, 4 Mar 2021 10:26:48 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:62167 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234338AbhCDP0Z (ORCPT ); Thu, 4 Mar 2021 10:26:25 -0500 Received: from fsav302.sakura.ne.jp (fsav302.sakura.ne.jp [153.120.85.133]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 124FP2Ot030921; Fri, 5 Mar 2021 00:25:02 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav302.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav302.sakura.ne.jp); Fri, 05 Mar 2021 00:25:02 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav302.sakura.ne.jp) Received: from localhost.localdomain (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 124FOtn6030882 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 5 Mar 2021 00:25:02 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) From: Tetsuo Handa To: Valentina Manea , Shuah Khan , Greg Kroah-Hartman Cc: Arnd Bergmann , linux-usb@vger.kernel.org, Tetsuo Handa Subject: [PATCH v4 06/12] usb: usbip: fix error handling of kthread_get_run() Date: Fri, 5 Mar 2021 00:24:49 +0900 Message-Id: <20210304152455.3685-7-penguin-kernel@I-love.SAKURA.ne.jp> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20210304152455.3685-1-penguin-kernel@I-love.SAKURA.ne.jp> References: <20210304152455.3685-1-penguin-kernel@I-love.SAKURA.ne.jp> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org syzbot is reporting an ERR_PTR(-EINTR) pointer dereference at vhci_shutdown_connection() [1], for kthread_create() became killable due to commit 786235eeba0e1e85 ("kthread: make kthread_create() killable"). When SIGKILLed while attach_store() is calling kthread_get_run(), ERR_PTR(-EINTR) is stored into vdev->ud.tcp_{rx,tx}, and then kthread_stop_put() is called on vdev->ud.tcp_{rx,tx} from vhci_shutdown_connection() because vdev->ud.tcp_{rx,tx} != NULL. Prior to commit 9720b4bc76a83807 ("staging/usbip: convert to kthread"), "current" pointer is assigned to vdev->ud.tcp_{rx,tx} by usbip_thread() kernel thread, and hence vdev->ud.tcp_{rx,tx} != NULL means a valid task pointer. Therefore, make kthread_get_run() return NULL when kthread_create() failed. This patch only fixes error pointer dereference problem, for the code prior to that commit was already providing manual recovery interface. [1] https://syzkaller.appspot.com/bug?extid=a93fba6d384346a761e3 Reported-by: syzbot Reported-by: syzbot Tested-by: syzbot Signed-off-by: Tetsuo Handa Fixes: 9720b4bc76a83807 ("staging/usbip: convert to kthread") Signed-off-by: Tetsuo Handa --- drivers/usb/usbip/usbip_common.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/usbip/usbip_common.h b/drivers/usb/usbip/usbip_common.h index f8e16c75b154..6e2a80b1633d 100644 --- a/drivers/usb/usbip/usbip_common.h +++ b/drivers/usb/usbip/usbip_common.h @@ -291,6 +291,8 @@ struct usbip_device { if (!IS_ERR(__k)) { \ get_task_struct(__k); \ wake_up_process(__k); \ + } else { \ + __k = NULL; \ } \ __k; \ })