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-pwm.c
/*
* Copyright (C) 2014 Philipp Zabel, Pengutronix
*
* 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.
*
* PWM (mis)used as clock output
*/
#include <linux/clk-provider.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
struct clk_pwm {
struct clk_hw hw;
struct pwm_device *pwm;
u32 fixed_rate;
};
static inline struct clk_pwm *to_clk_pwm(struct clk_hw *hw)
{
return container_of(hw, struct clk_pwm, hw);
}
static int clk_pwm_prepare(struct clk_hw *hw)
{
struct clk_pwm *clk_pwm = to_clk_pwm(hw);
return pwm_enable(clk_pwm->pwm);
}
static void clk_pwm_unprepare(struct clk_hw *hw)
{
struct clk_pwm *clk_pwm = to_clk_pwm(hw);
pwm_disable(clk_pwm->pwm);
}
static unsigned long clk_pwm_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_pwm *clk_pwm = to_clk_pwm(hw);
return clk_pwm->fixed_rate;
}
static const struct clk_ops clk_pwm_ops = {
.prepare = clk_pwm_prepare,
.unprepare = clk_pwm_unprepare,
.recalc_rate = clk_pwm_recalc_rate,
};
static int clk_pwm_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
struct clk_init_data init;
struct clk_pwm *clk_pwm;
struct pwm_device *pwm;
const char *clk_name;
struct clk *clk;
int ret;
clk_pwm = devm_kzalloc(&pdev->dev, sizeof(*clk_pwm), GFP_KERNEL);
if (!clk_pwm)
return -ENOMEM;
pwm = devm_pwm_get(&pdev->dev, NULL);
if (IS_ERR(pwm))
return PTR_ERR(pwm);
if (!pwm->period) {
dev_err(&pdev->dev, "invalid PWM period\n");
return -EINVAL;
}
if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate))
clk_pwm->fixed_rate = NSEC_PER_SEC / pwm->period;
if (pwm->period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
pwm->period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
dev_err(&pdev->dev,
"clock-frequency does not match PWM period\n");
return -EINVAL;
}
ret = pwm_config(pwm, (pwm->period + 1) >> 1, pwm->period);
if (ret < 0)
return ret;
clk_name = node->name;
of_property_read_string(node, "clock-output-names", &clk_name);
init.name = clk_name;
init.ops = &clk_pwm_ops;
init.flags = CLK_IS_BASIC | CLK_IS_ROOT;
init.num_parents = 0;
clk_pwm->pwm = pwm;
clk_pwm->hw.init = &init;
clk = devm_clk_register(&pdev->dev, &clk_pwm->hw);
if (IS_ERR(clk))
return PTR_ERR(clk);
return of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
static int clk_pwm_remove(struct platform_device *pdev)
{
of_clk_del_provider(pdev->dev.of_node);
return 0;
}
static const struct of_device_id clk_pwm_dt_ids[] = {
{ .compatible = "pwm-clock" },
{ }
};
MODULE_DEVICE_TABLE(of, clk_pwm_dt_ids);
static struct platform_driver clk_pwm_driver = {
.probe = clk_pwm_probe,
.remove = clk_pwm_remove,
.driver = {
.name = "pwm-clock",
.of_match_table = of_match_ptr(clk_pwm_dt_ids),
},
};
module_platform_driver(clk_pwm_driver);
MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
MODULE_DESCRIPTION("PWM clock driver");
MODULE_LICENSE("GPL");
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