Revision 85bd839983778fcd0c1c043327b14a046e979b39 authored by Gu Zheng on 10 June 2015, 18:14:43 UTC, committed by Linus Torvalds on 10 June 2015, 23:43:43 UTC
Izumi found the following oops when hot re-adding a node:
BUG: unable to handle kernel paging request at ffffc90008963690
IP: __wake_up_bit+0x20/0x70
Oops: 0000 [#1] SMP
CPU: 68 PID: 1237 Comm: rs:main Q:Reg Not tainted 4.1.0-rc5 #80
Hardware name: FUJITSU PRIMEQUEST2800E/SB, BIOS PRIMEQUEST 2000 Series BIOS Version 1.87 04/28/2015
task: ffff880838df8000 ti: ffff880017b94000 task.ti: ffff880017b94000
RIP: 0010:[<ffffffff810dff80>] [<ffffffff810dff80>] __wake_up_bit+0x20/0x70
RSP: 0018:ffff880017b97be8 EFLAGS: 00010246
RAX: ffffc90008963690 RBX: 00000000003c0000 RCX: 000000000000a4c9
RDX: 0000000000000000 RSI: ffffea101bffd500 RDI: ffffc90008963648
RBP: ffff880017b97c08 R08: 0000000002000020 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a0797c73800
R13: ffffea101bffd500 R14: 0000000000000001 R15: 00000000003c0000
FS: 00007fcc7ffff700(0000) GS:ffff880874800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc90008963690 CR3: 0000000836761000 CR4: 00000000001407e0
Call Trace:
unlock_page+0x6d/0x70
generic_write_end+0x53/0xb0
xfs_vm_write_end+0x29/0x80 [xfs]
generic_perform_write+0x10a/0x1e0
xfs_file_buffered_aio_write+0x14d/0x3e0 [xfs]
xfs_file_write_iter+0x79/0x120 [xfs]
__vfs_write+0xd4/0x110
vfs_write+0xac/0x1c0
SyS_write+0x58/0xd0
system_call_fastpath+0x12/0x76
Code: 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 45 f8 31 c0 48 8d 47 48 <48> 39 47 48 48 c7 45 e8 00 00 00 00 48 c7 45 f0 00 00 00 00 48
RIP [<ffffffff810dff80>] __wake_up_bit+0x20/0x70
RSP <ffff880017b97be8>
CR2: ffffc90008963690
Reproduce method (re-add a node)::
Hot-add nodeA --> remove nodeA --> hot-add nodeA (panic)
This seems an use-after-free problem, and the root cause is
zone->wait_table was not set to *NULL* after free it in
try_offline_node.
When hot re-add a node, we will reuse the pgdat of it, so does the zone
struct, and when add pages to the target zone, it will init the zone
first (including the wait_table) if the zone is not initialized. The
judgement of zone initialized is based on zone->wait_table:
static inline bool zone_is_initialized(struct zone *zone)
{
return !!zone->wait_table;
}
so if we do not set the zone->wait_table to *NULL* after free it, the
memory hotplug routine will skip the init of new zone when hot re-add
the node, and the wait_table still points to the freed memory, then we
will access the invalid address when trying to wake up the waiting
people after the i/o operation with the page is done, such as mentioned
above.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reported-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Reviewed by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 5879ae5
clk-max77802.c
/*
* clk-max77802.c - Clock driver for Maxim 77802
*
* Copyright (C) 2014 Google, Inc
*
* Copyright (C) 2012 Samsung Electornics
* Jonghwa Lee <jonghwa3.lee@samsung.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* This driver is based on clk-max77686.c
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/mfd/max77686-private.h>
#include <linux/clk-provider.h>
#include <linux/mutex.h>
#include <linux/clkdev.h>
#include <dt-bindings/clock/maxim,max77802.h>
#include "clk-max-gen.h"
#define MAX77802_CLOCK_OPMODE_MASK 0x1
#define MAX77802_CLOCK_LOW_JITTER_SHIFT 0x3
static struct clk_init_data max77802_clks_init[MAX77802_CLKS_NUM] = {
[MAX77802_CLK_32K_AP] = {
.name = "32khz_ap",
.ops = &max_gen_clk_ops,
.flags = CLK_IS_ROOT,
},
[MAX77802_CLK_32K_CP] = {
.name = "32khz_cp",
.ops = &max_gen_clk_ops,
.flags = CLK_IS_ROOT,
},
};
static int max77802_clk_probe(struct platform_device *pdev)
{
struct max77686_dev *iodev = dev_get_drvdata(pdev->dev.parent);
int ret;
ret = max_gen_clk_probe(pdev, iodev->regmap, MAX77802_REG_32KHZ,
max77802_clks_init, MAX77802_CLKS_NUM);
if (ret) {
dev_err(&pdev->dev, "generic probe failed %d\n", ret);
return ret;
}
/* Enable low-jitter mode on the 32khz clocks. */
ret = regmap_update_bits(iodev->regmap, MAX77802_REG_32KHZ,
1 << MAX77802_CLOCK_LOW_JITTER_SHIFT,
1 << MAX77802_CLOCK_LOW_JITTER_SHIFT);
if (ret < 0)
dev_err(&pdev->dev, "failed to enable low-jitter mode\n");
return ret;
}
static int max77802_clk_remove(struct platform_device *pdev)
{
return max_gen_clk_remove(pdev, MAX77802_CLKS_NUM);
}
static const struct platform_device_id max77802_clk_id[] = {
{ "max77802-clk", 0},
{ },
};
MODULE_DEVICE_TABLE(platform, max77802_clk_id);
static struct platform_driver max77802_clk_driver = {
.driver = {
.name = "max77802-clk",
},
.probe = max77802_clk_probe,
.remove = max77802_clk_remove,
.id_table = max77802_clk_id,
};
module_platform_driver(max77802_clk_driver);
MODULE_DESCRIPTION("MAXIM 77802 Clock Driver");
MODULE_AUTHOR("Javier Martinez Canillas <javier.martinez@collabora.co.uk>");
MODULE_LICENSE("GPL");
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