Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S935608AbdCJJ3A (ORCPT <rfc822;w@1wt.eu>);
        Fri, 10 Mar 2017 04:29:00 -0500
Received: from mail.linuxfoundation.org ([140.211.169.12]:39648 "EHLO
        mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S934942AbdCJJ24 (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 10 Mar 2017 04:28:56 -0500
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Wang Nan <wangnan0@huawei.com>,
        Xia Kaixu <xiakaixu@huawei.com>, Li Zefan <lizefan@huawei.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4.10 038/167] coresight: fix kernel panic caused by invalid CPU
Date: Fri, 10 Mar 2017 10:08:01 +0100
Message-Id: <20170310083959.417193928@linuxfoundation.org>
X-Mailer: git-send-email 2.12.0
In-Reply-To: <20170310083956.767605269@linuxfoundation.org>
References: <20170310083956.767605269@linuxfoundation.org>
User-Agent: quilt/0.65
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2852
Lines: 73

4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wang Nan <wangnan0@huawei.com>

commit f09444639099584bc4784dfcd85ada67c6f33e0f upstream.

Commit d52c9750f150 ("coresight: reset "enable_sink" flag when need be")
caused a kernel panic because of the using of an invalid value: after
'for_each_cpu(cpu, mask)', value of local variable 'cpu' become invalid,
causes following 'cpu_to_node' access invalid memory area.

This patch brings the deleted 'cpu = cpumask_first(mask)' back.

Panic log:

 $ perf record -e cs_etm// ls

 Unable to handle kernel paging request at virtual address fffe801804af4f10
 pgd = ffff8017ce031600
 [fffe801804af4f10] *pgd=0000000000000000, *pud=0000000000000000
 Internal error: Oops: 96000004 [#1] SMP
 Modules linked in:
 CPU: 33 PID: 1619 Comm: perf Not tainted 4.7.1+ #16
 Hardware name: Huawei Taishan 2280 /CH05TEVBA, BIOS 1.10 11/24/2016
 task: ffff8017cb0c8400 ti: ffff8017cb154000 task.ti: ffff8017cb154000
 PC is at tmc_alloc_etf_buffer+0x60/0xd4
 LR is at tmc_alloc_etf_buffer+0x44/0xd4
 pc : [<ffff000008633df8>] lr : [<ffff000008633ddc>] pstate: 60000145
 sp : ffff8017cb157b40
 x29: ffff8017cb157b40 x28: 0000000000000000
 ...skip...
 7a60: ffff000008c64dc8 0000000000000006 0000000000000253 ffffffffffffffff
 7a80: 0000000000000000 0000000000000000 ffff0000080872cc 0000000000000001
 [<ffff000008633df8>] tmc_alloc_etf_buffer+0x60/0xd4
 [<ffff000008632b9c>] etm_setup_aux+0x1dc/0x1e8
 [<ffff00000816eed4>] rb_alloc_aux+0x2b0/0x338
 [<ffff00000816a5e4>] perf_mmap+0x414/0x568
 [<ffff0000081ab694>] mmap_region+0x324/0x544
 [<ffff0000081abbe8>] do_mmap+0x334/0x3e0
 [<ffff000008191150>] vm_mmap_pgoff+0xa4/0xc8
 [<ffff0000081a9a30>] SyS_mmap_pgoff+0xb0/0x22c
 [<ffff0000080872e4>] sys_mmap+0x18/0x28
 [<ffff0000080843f0>] el0_svc_naked+0x24/0x28
 Code: 912040a5 d0001c00 f873d821 911c6000 (b8656822)
 ---[ end trace 98933da8f92b0c9a ]---

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Xia Kaixu <xiakaixu@huawei.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Fixes: d52c9750f150 ("coresight: reset "enable_sink" flag when need be")
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/hwtracing/coresight/coresight-etm-perf.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -242,6 +242,7 @@ static void *etm_setup_aux(int event_cpu
 	if (!sink_ops(sink)->alloc_buffer)
 		goto err;
 
+	cpu = cpumask_first(mask);
 	/* Get the AUX specific data from the sink buffer */
 	event_data->snk_config =
 			sink_ops(sink)->alloc_buffer(sink, cpu, pages,