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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 6386FC10F11 for ; Wed, 24 Apr 2019 18:06:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2AAF920652 for ; Wed, 24 Apr 2019 18:06:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556129190; bh=VOb9Bwitmue9DiAYWxTTRHG6niZSlzsQsKGb8HdT0Do=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ehs+LPtgQHeRvJDBU16TbzwyYMEy/0kfwLtBdI6Q/GyMqg7oNpR3uVdC0KA5UKJOP h5WGxOQrlfhQO0FaKs8bQvRVG8Paxy7EgRiwYh5uFuqdBsLkU2R+ZvfRywhhVn8GKA rFbhlQStjkQz9J9I6kfj3p4stCWr4Z/YZVVrs+Sk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387885AbfDXRRv (ORCPT ); Wed, 24 Apr 2019 13:17:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:42762 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388715AbfDXRRr (ORCPT ); Wed, 24 Apr 2019 13:17:47 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 99723218B0; Wed, 24 Apr 2019 17:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126267; bh=VOb9Bwitmue9DiAYWxTTRHG6niZSlzsQsKGb8HdT0Do=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BRvVFgBYdrQcz9mXLLQFLcqsjxBaj0+SxnreCPy5iO9izBTDOifN9wqCSnk4q20jR fD9BX1fL6s6nJZdWOAZFjG3xbyx7SpbtSfPYdJqnPrhCe6HnLgxGMWI+lv+u6rPFoF xPD0f2hEoakKFd6wzucP8GMl5gVrNd65NljAWdms= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+fdc00003f4efff43bc5b@syzkaller.appspotmail.com, Myungho Jung , Marcel Holtmann , Zubin Mithra Subject: [PATCH 4.4 008/168] Bluetooth: Fix decrementing reference count twice in releasing socket Date: Wed, 24 Apr 2019 19:07:32 +0200 Message-Id: <20190424170923.969536865@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170923.452349382@linuxfoundation.org> References: <20190424170923.452349382@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Myungho Jung commit e20a2e9c42c9e4002d9e338d74e7819e88d77162 upstream. When releasing socket, it is possible to enter hci_sock_release() and hci_sock_dev_event(HCI_DEV_UNREG) at the same time in different thread. The reference count of hdev should be decremented only once from one of them but if storing hdev to local variable in hci_sock_release() before detached from socket and setting to NULL in hci_sock_dev_event(), hci_dev_put(hdev) is unexpectedly called twice. This is resolved by referencing hdev from socket after bt_sock_unlink() in hci_sock_release(). Reported-by: syzbot+fdc00003f4efff43bc5b@syzkaller.appspotmail.com Signed-off-by: Myungho Jung Signed-off-by: Marcel Holtmann Signed-off-by: Zubin Mithra Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/hci_sock.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -558,13 +558,12 @@ static int hci_sock_release(struct socke if (!sk) return 0; - hdev = hci_pi(sk)->hdev; - if (hci_pi(sk)->channel == HCI_CHANNEL_MONITOR) atomic_dec(&monitor_promisc); bt_sock_unlink(&hci_sk_list, sk); + hdev = hci_pi(sk)->hdev; if (hdev) { if (hci_pi(sk)->channel == HCI_CHANNEL_USER) { /* When releasing an user channel exclusive access,