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=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 5DC3CC10F11 for ; Wed, 24 Apr 2019 18:09:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24E3B204EC for ; Wed, 24 Apr 2019 18:09:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556129354; bh=2SErRLCqs0eCxuxqFUVpnt/ed7rfWF9J62ePGQWR4as=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=L4P3U5NlnYGhCdPPVREcXJe9NsJD/ykpwR0a9VQKFCEeYRJs2p/LRDH5s6NEt56Cs McnkQ/6Dd9YDyndvt9j9va3O+q+J1cVD0p1dXPRVTOPWlM/U/HoBxvcqdQNkMs0dWC UI/QgJ2SU4QsOwCL4+6roKVRpaGbw3uuaI9jXXyI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389094AbfDXSJM (ORCPT ); Wed, 24 Apr 2019 14:09:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:39932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388231AbfDXRP1 (ORCPT ); Wed, 24 Apr 2019 13:15:27 -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 D74C621909; Wed, 24 Apr 2019 17:15:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126127; bh=2SErRLCqs0eCxuxqFUVpnt/ed7rfWF9J62ePGQWR4as=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TaByP99sCWMOw0moRRrIbRchx/9RFAbx1OiWgfFSHskNzdrJZnndm1iqeUXim6X9u jpeJs9qKWD4huvhzXP2zgC0RTQL4sSbPYR8HLPingQ2Iqj5AtWY8cExjseL3+zQy7Q W83zxomrxoS0vUjmgxnkDW9xGfjzz+aswZe2VteA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jann Horn , Michal Hocko , Tejun Heo Subject: [PATCH 3.18 104/104] device_cgroup: fix RCU imbalance in error case Date: Wed, 24 Apr 2019 19:10:01 +0200 Message-Id: <20190424170910.915755642@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170839.996641496@linuxfoundation.org> References: <20190424170839.996641496@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: Jann Horn commit 0fcc4c8c044e117ac126ab6df4138ea9a67fa2a9 upstream. When dev_exception_add() returns an error (due to a failed memory allocation), make sure that we move the RCU preemption count back to where it was before we were called. We dropped the RCU read lock inside the loop body, so we can't just "break". sparse complains about this, too: $ make -s C=2 security/device_cgroup.o ./include/linux/rcupdate.h:647:9: warning: context imbalance in 'propagate_exception' - unexpected unlock Fixes: d591fb56618f ("device_cgroup: simplify cgroup tree walk in propagate_exception()") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Acked-by: Michal Hocko Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- security/device_cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -568,7 +568,7 @@ static int propagate_exception(struct de devcg->behavior == DEVCG_DEFAULT_ALLOW) { rc = dev_exception_add(devcg, ex); if (rc) - break; + return rc; } else { /* * in the other possible cases: