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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 C4061C2BB55 for ; Thu, 16 Apr 2020 14:31:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A465321D7E for ; Thu, 16 Apr 2020 14:31:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587047504; bh=LoTfbwCSaBF2QyTddDg0v6TEKT+rRRwgXkOpkMtXQUQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RGHGIokjYWICB+uXRkkWVrbDshPQrA7c7lTtipQqWZa02HpUekyxkiZjJjkDdoZbT c1lIEIknj8zoEymsJAlga5rYX3zIFcQjMnaxaqqBWhvXo9TxXUdX2r+tDd1oEtIIAT U917Ndvp08YBCYXoV4B2VUCVDQNVYjfroVjTHjmY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388314AbgDPObn (ORCPT ); Thu, 16 Apr 2020 10:31:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:49800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409631AbgDPOCT (ORCPT ); Thu, 16 Apr 2020 10:02:19 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 43E01217D8; Thu, 16 Apr 2020 14:02:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587045738; bh=LoTfbwCSaBF2QyTddDg0v6TEKT+rRRwgXkOpkMtXQUQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o5DGY79eq8A8W0PHLM2UWBPZHi7sd7EfK4H41UmdR7UYDhsSsDYXrDYxqeYO+Uisu Id15GnGStknL8E6ouBF+EUtjx9sJvBKlt0Xm9bEJtglE3cno5vl4JFw3YL3UB3P6pq GPaR2NGseYPrwe0gbeKFSuPzEmysJj7qorS3ig4g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver OHalloran , "Gautham R. Shenoy" , Michael Ellerman Subject: [PATCH 5.6 229/254] cpufreq: powernv: Fix use-after-free Date: Thu, 16 Apr 2020 15:25:18 +0200 Message-Id: <20200416131354.328403598@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200416131325.804095985@linuxfoundation.org> References: <20200416131325.804095985@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: Oliver O'Halloran commit d0a72efac89d1c35ac55197895201b7b94c5e6ef upstream. The cpufreq driver has a use-after-free that we can hit if: a) There's an OCC message pending when the notifier is registered, and b) The cpufreq driver fails to register with the core. When a) occurs the notifier schedules a workqueue item to handle the message. The backing work_struct is located on chips[].throttle and when b) happens we clean up by freeing the array. Once we get to the (now free) queued item and the kernel crashes. Fixes: c5e29ea7ac14 ("cpufreq: powernv: Fix bugs in powernv_cpufreq_{init/exit}") Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Oliver O'Halloran Reviewed-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200206062622.28235-1-oohall@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/powernv-cpufreq.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -1080,6 +1080,12 @@ free_and_return: static inline void clean_chip_info(void) { + int i; + + /* flush any pending work items */ + if (chips) + for (i = 0; i < nr_chips; i++) + cancel_work_sync(&chips[i].throttle); kfree(chips); }