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
Raw File
common.c
/*
 * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

#include <linux/export.h>
#include <linux/regmap.h>
#include <linux/platform_device.h>
#include <linux/clk-provider.h>
#include <linux/reset-controller.h>

#include "common.h"
#include "clk-rcg.h"
#include "clk-regmap.h"
#include "reset.h"

struct qcom_cc {
	struct qcom_reset_controller reset;
	struct clk_onecell_data data;
	struct clk *clks[];
};

const
struct freq_tbl *qcom_find_freq(const struct freq_tbl *f, unsigned long rate)
{
	if (!f)
		return NULL;

	for (; f->freq; f++)
		if (rate <= f->freq)
			return f;

	/* Default to our fastest rate */
	return f - 1;
}
EXPORT_SYMBOL_GPL(qcom_find_freq);

int qcom_find_src_index(struct clk_hw *hw, const struct parent_map *map, u8 src)
{
	int i, num_parents = __clk_get_num_parents(hw->clk);

	for (i = 0; i < num_parents; i++)
		if (src == map[i].src)
			return i;

	return -ENOENT;
}
EXPORT_SYMBOL_GPL(qcom_find_src_index);

struct regmap *
qcom_cc_map(struct platform_device *pdev, const struct qcom_cc_desc *desc)
{
	void __iomem *base;
	struct resource *res;
	struct device *dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	base = devm_ioremap_resource(dev, res);
	if (IS_ERR(base))
		return ERR_CAST(base);

	return devm_regmap_init_mmio(dev, base, desc->config);
}
EXPORT_SYMBOL_GPL(qcom_cc_map);

int qcom_cc_really_probe(struct platform_device *pdev,
			 const struct qcom_cc_desc *desc, struct regmap *regmap)
{
	int i, ret;
	struct device *dev = &pdev->dev;
	struct clk *clk;
	struct clk_onecell_data *data;
	struct clk **clks;
	struct qcom_reset_controller *reset;
	struct qcom_cc *cc;
	size_t num_clks = desc->num_clks;
	struct clk_regmap **rclks = desc->clks;

	cc = devm_kzalloc(dev, sizeof(*cc) + sizeof(*clks) * num_clks,
			  GFP_KERNEL);
	if (!cc)
		return -ENOMEM;

	clks = cc->clks;
	data = &cc->data;
	data->clks = clks;
	data->clk_num = num_clks;

	for (i = 0; i < num_clks; i++) {
		if (!rclks[i]) {
			clks[i] = ERR_PTR(-ENOENT);
			continue;
		}
		clk = devm_clk_register_regmap(dev, rclks[i]);
		if (IS_ERR(clk))
			return PTR_ERR(clk);
		clks[i] = clk;
	}

	ret = of_clk_add_provider(dev->of_node, of_clk_src_onecell_get, data);
	if (ret)
		return ret;

	reset = &cc->reset;
	reset->rcdev.of_node = dev->of_node;
	reset->rcdev.ops = &qcom_reset_ops;
	reset->rcdev.owner = dev->driver->owner;
	reset->rcdev.nr_resets = desc->num_resets;
	reset->regmap = regmap;
	reset->reset_map = desc->resets;
	platform_set_drvdata(pdev, &reset->rcdev);

	ret = reset_controller_register(&reset->rcdev);
	if (ret)
		of_clk_del_provider(dev->of_node);

	return ret;
}
EXPORT_SYMBOL_GPL(qcom_cc_really_probe);

int qcom_cc_probe(struct platform_device *pdev, const struct qcom_cc_desc *desc)
{
	struct regmap *regmap;

	regmap = qcom_cc_map(pdev, desc);
	if (IS_ERR(regmap))
		return PTR_ERR(regmap);

	return qcom_cc_really_probe(pdev, desc, regmap);
}
EXPORT_SYMBOL_GPL(qcom_cc_probe);

void qcom_cc_remove(struct platform_device *pdev)
{
	of_clk_del_provider(pdev->dev.of_node);
	reset_controller_unregister(platform_get_drvdata(pdev));
}
EXPORT_SYMBOL_GPL(qcom_cc_remove);
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