From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-4000417-1517256401-2-3480078727087052248 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1517256400; b=B8i+UTITLl5bEv3WOlVGBWbPaTzF5/9iYAy6QtFl0O9GHyP TeHv60EsT0cscjqBoiSiWfgV7pWUMpwNYKTwhwUYClxRBx05UDW5PfphoVAvlaJv NwAhQcmPULna/uqQ0qaLivS0hyKsOL6IlHZa9sxQlzrvj4/xcSpiX42Xx/chYSce cyHlvgySbjy2lQme5ncz4mYFuULZ0B4G5FHWF4w9mbiCd9D/kk3u0J1cJJDZeFK8 AWA5gQkhq3a6mDHILCUPC3cawDQcIKG8HUE4Md6KNKzM54kQx0FmIy3k/Od9QZuE EseOcw8QUprpXibzwVf9L1425j0ASNXTfJqCGiA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1517256400; bh=F6uD+N686pQO2Y+F5Opc43hekY rquC/J1upu7JKfBmo=; b=l3KgZ017BKJ8rprWDl5h07YTidNCp4IfDqAAbk65LW sHQIqMigelorGN/fi7dvDky7FBXK+KrnA71VjFPuoQ5O8yTpy/HHnHadRj7OngSC 628Csjk0NsdD5MVjGYI7AeFAwsJ4qsuF/DLcuNtIHBS8oaZ/MSU3xTB6j4Z7pTGm UVhDJhG+y9Ts06kQHPMiTPpAGQlWdxUbca7svP1UHltyEjHs2O775xBfML1HhKGU zDie9R0UHfZeU0yPDu28Ht0P6Fl6FtQhblxtRLjZyuCRSvHhfPQ6hxXBYzq56/Sq oZK7DmWnqy1kgoEa2fLGSlLYx687n4+WkJsqZ75+Vksg== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752749AbeA2UGh (ORCPT ); Mon, 29 Jan 2018 15:06:37 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:48578 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752723AbeA2UGf (ORCPT ); Mon, 29 Jan 2018 15:06:35 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guillaume Nault , "David S. Miller" Subject: [PATCH 4.9 49/66] ppp: unlock all_ppp_mutex before registering device Date: Mon, 29 Jan 2018 13:57:13 +0100 Message-Id: <20180129123842.470749789@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180129123839.842860149@linuxfoundation.org> References: <20180129123839.842860149@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guillaume Nault [ Upstream commit 0171c41835591e9aa2e384b703ef9a6ae367c610 ] ppp_dev_uninit(), which is the .ndo_uninit() handler of PPP devices, needs to lock pn->all_ppp_mutex. Therefore we mustn't call register_netdevice() with pn->all_ppp_mutex already locked, or we'd deadlock in case register_netdevice() fails and calls .ndo_uninit(). Fortunately, we can unlock pn->all_ppp_mutex before calling register_netdevice(). This lock protects pn->units_idr, which isn't used in the device registration process. However, keeping pn->all_ppp_mutex locked during device registration did ensure that no device in transient state would be published in pn->units_idr. In practice, unlocking it before calling register_netdevice() doesn't change this property: ppp_unit_register() is called with 'ppp_mutex' locked and all searches done in pn->units_idr hold this lock too. Fixes: 8cb775bc0a34 ("ppp: fix device unregistration upon netns deletion") Reported-and-tested-by: syzbot+367889b9c9e279219175@syzkaller.appspotmail.com Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ppp/ppp_generic.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -1002,17 +1002,18 @@ static int ppp_unit_register(struct ppp if (!ifname_is_set) snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index); + mutex_unlock(&pn->all_ppp_mutex); + ret = register_netdevice(ppp->dev); if (ret < 0) goto err_unit; atomic_inc(&ppp_unit_count); - mutex_unlock(&pn->all_ppp_mutex); - return 0; err_unit: + mutex_lock(&pn->all_ppp_mutex); unit_put(&pn->units_idr, ppp->file.index); err: mutex_unlock(&pn->all_ppp_mutex);