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,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 B6B2BC2D0D1 for ; Sun, 29 Dec 2019 18:00:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C986206A4 for ; Sun, 29 Dec 2019 18:00:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577642420; bh=tLimZJIgN2Fma8fEKXPYFx7UStdsZvk3pJGF5ppdUDg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ebkMuirT9wpN6E4dP762WOVzPz6aGvTYWTkDhNSJmX1v434Je4LTbgeQadDa9aBbE qpAmWhXLl++U/8r6puTE487c+c8F1kil3w1/0rtpnk0hZDnsizd7d2S3wZ+hWYa8/O J8CVeq/CqNt0P5tLzfOLc41a+jihykXQkzRRLrVE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733240AbfL2R50 (ORCPT ); Sun, 29 Dec 2019 12:57:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:47906 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732963AbfL2R5Z (ORCPT ); Sun, 29 Dec 2019 12:57:25 -0500 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 189B121744; Sun, 29 Dec 2019 17:57:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577642244; bh=tLimZJIgN2Fma8fEKXPYFx7UStdsZvk3pJGF5ppdUDg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y8V9ijcFHlM3duXG3otxy1SxxAHdvrryX3Niazv5e1XReAaPa25+W5pJLTw841l6w VyXS6/JO9Nae82w12sh3GzPTTzUhHU2qFONzQjrCRI/0MREtczdX498qHSE4y8LrYy AZ0BybLjbxLm5vpD1KLPGX//gKbEVKrbnSNq0Op0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Shishkin , Andy Shevchenko , Ammy Yi Subject: [PATCH 5.4 401/434] intel_th: msu: Fix window switching without windows Date: Sun, 29 Dec 2019 18:27:34 +0100 Message-Id: <20191229172729.149072010@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191229172702.393141737@linuxfoundation.org> References: <20191229172702.393141737@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Alexander Shishkin commit 05b686b573cfb35a227c30787083a6631ff0f0c9 upstream. Commit 6cac7866c2741 ("intel_th: msu: Add a sysfs attribute to trigger window switch") adds a NULL pointer dereference in the case when there are no windows allocated: > BUG: kernel NULL pointer dereference, address: 0000000000000000 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 0 P4D 0 > Oops: 0000 1 SMP > CPU: 5 PID: 1110 Comm: bash Not tainted 5.5.0-rc1+ #1 > RIP: 0010:msc_win_switch+0xa/0x80 [intel_th_msu] > Call Trace: > ? win_switch_store+0x9b/0xc0 [intel_th_msu] > dev_attr_store+0x17/0x30 > sysfs_kf_write+0x3e/0x50 > kernfs_fop_write+0xda/0x1b0 > __vfs_write+0x1b/0x40 > vfs_write+0xb9/0x1a0 > ksys_write+0x67/0xe0 > __x64_sys_write+0x1a/0x20 > do_syscall_64+0x57/0x1d0 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix that by disallowing window switching with multiwindow buffers without windows. Signed-off-by: Alexander Shishkin Fixes: 6cac7866c274 ("intel_th: msu: Add a sysfs attribute to trigger window switch") Reviewed-by: Andy Shevchenko Reported-by: Ammy Yi Tested-by: Ammy Yi Cc: stable@vger.kernel.org # v5.2+ Link: https://lore.kernel.org/r/20191217115527.74383-5-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/intel_th/msu.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -1676,10 +1676,13 @@ static int intel_th_msc_init(struct msc return 0; } -static void msc_win_switch(struct msc *msc) +static int msc_win_switch(struct msc *msc) { struct msc_window *first; + if (list_empty(&msc->win_list)) + return -EINVAL; + first = list_first_entry(&msc->win_list, struct msc_window, entry); if (msc_is_last_win(msc->cur_win)) @@ -1691,6 +1694,8 @@ static void msc_win_switch(struct msc *m msc->base_addr = msc_win_base_dma(msc->cur_win); intel_th_trace_switch(msc->thdev); + + return 0; } /** @@ -2025,16 +2030,15 @@ win_switch_store(struct device *dev, str if (val != 1) return -EINVAL; + ret = -EINVAL; mutex_lock(&msc->buf_mutex); /* * Window switch can only happen in the "multi" mode. * If a external buffer is engaged, they have the full * control over window switching. */ - if (msc->mode != MSC_MODE_MULTI || msc->mbuf) - ret = -ENOTSUPP; - else - msc_win_switch(msc); + if (msc->mode == MSC_MODE_MULTI && !msc->mbuf) + ret = msc_win_switch(msc); mutex_unlock(&msc->buf_mutex); return ret ? ret : size;