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
clk-pll.h
/*
 * Copyright (c) 2013 Samsung Electronics Co., Ltd.
 * Copyright (c) 2013 Linaro Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Common Clock Framework support for all PLL's in Samsung platforms
*/

#ifndef __SAMSUNG_CLK_PLL_H
#define __SAMSUNG_CLK_PLL_H

enum samsung_pll_type {
	pll_2126,
	pll_3000,
	pll_35xx,
	pll_36xx,
	pll_2550,
	pll_2650,
	pll_4500,
	pll_4502,
	pll_4508,
	pll_4600,
	pll_4650,
	pll_4650c,
	pll_6552,
	pll_6552_s3c2416,
	pll_6553,
	pll_s3c2410_mpll,
	pll_s3c2410_upll,
	pll_s3c2440_mpll,
	pll_2550xx,
	pll_2650xx,
	pll_1450x,
	pll_1451x,
	pll_1452x,
	pll_1460x,
};

#define PLL_35XX_RATE(_rate, _m, _p, _s)			\
	{							\
		.rate	=	(_rate),				\
		.mdiv	=	(_m),				\
		.pdiv	=	(_p),				\
		.sdiv	=	(_s),				\
	}

#define PLL_36XX_RATE(_rate, _m, _p, _s, _k)			\
	{							\
		.rate	=	(_rate),				\
		.mdiv	=	(_m),				\
		.pdiv	=	(_p),				\
		.sdiv	=	(_s),				\
		.kdiv	=	(_k),				\
	}

#define PLL_45XX_RATE(_rate, _m, _p, _s, _afc)			\
	{							\
		.rate	=	(_rate),			\
		.mdiv	=	(_m),				\
		.pdiv	=	(_p),				\
		.sdiv	=	(_s),				\
		.afc	=	(_afc),				\
	}

#define PLL_4600_RATE(_rate, _m, _p, _s, _k, _vsel)		\
	{							\
		.rate	=	(_rate),			\
		.mdiv	=	(_m),				\
		.pdiv	=	(_p),				\
		.sdiv	=	(_s),				\
		.kdiv	=	(_k),				\
		.vsel	=	(_vsel),			\
	}

#define PLL_4650_RATE(_rate, _m, _p, _s, _k, _mfr, _mrr, _vsel)	\
	{							\
		.rate	=	(_rate),			\
		.mdiv	=	(_m),				\
		.pdiv	=	(_p),				\
		.sdiv	=	(_s),				\
		.kdiv	=	(_k),				\
		.mfr	=	(_mfr),				\
		.mrr	=	(_mrr),				\
		.vsel	=	(_vsel),			\
	}

/* NOTE: Rate table should be kept sorted in descending order. */

struct samsung_pll_rate_table {
	unsigned int rate;
	unsigned int pdiv;
	unsigned int mdiv;
	unsigned int sdiv;
	unsigned int kdiv;
	unsigned int afc;
	unsigned int mfr;
	unsigned int mrr;
	unsigned int vsel;
};

extern struct clk * __init samsung_clk_register_pll2550x(const char *name,
			const char *pname, const void __iomem *reg_base,
			const unsigned long offset);

#endif /* __SAMSUNG_CLK_PLL_H */
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