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
cpuidle-ux500.c
/*
* Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
*
* Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
* and Jonas Aaberg <jonas.aberg@stericsson.com>.
*
* 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.
*/
#include <linux/module.h>
#include <linux/cpuidle.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/smp.h>
#include <linux/mfd/dbx500-prcmu.h>
#include <linux/platform_data/arm-ux500-pm.h>
#include <linux/platform_device.h>
#include <asm/cpuidle.h>
static atomic_t master = ATOMIC_INIT(0);
static DEFINE_SPINLOCK(master_lock);
static inline int ux500_enter_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
int this_cpu = smp_processor_id();
bool recouple = false;
if (atomic_inc_return(&master) == num_online_cpus()) {
/* With this lock, we prevent the other cpu to exit and enter
* this function again and become the master */
if (!spin_trylock(&master_lock))
goto wfi;
/* decouple the gic from the A9 cores */
if (prcmu_gic_decouple()) {
spin_unlock(&master_lock);
goto out;
}
/* If an error occur, we will have to recouple the gic
* manually */
recouple = true;
/* At this state, as the gic is decoupled, if the other
* cpu is in WFI, we have the guarantee it won't be wake
* up, so we can safely go to retention */
if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
goto out;
/* The prcmu will be in charge of watching the interrupts
* and wake up the cpus */
if (prcmu_copy_gic_settings())
goto out;
/* Check in the meantime an interrupt did
* not occur on the gic ... */
if (prcmu_gic_pending_irq())
goto out;
/* ... and the prcmu */
if (prcmu_pending_irq())
goto out;
/* Go to the retention state, the prcmu will wait for the
* cpu to go WFI and this is what happens after exiting this
* 'master' critical section */
if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
goto out;
/* When we switch to retention, the prcmu is in charge
* of recoupling the gic automatically */
recouple = false;
spin_unlock(&master_lock);
}
wfi:
cpu_do_idle();
out:
atomic_dec(&master);
if (recouple) {
prcmu_gic_recouple();
spin_unlock(&master_lock);
}
return index;
}
static struct cpuidle_driver ux500_idle_driver = {
.name = "ux500_idle",
.owner = THIS_MODULE,
.states = {
ARM_CPUIDLE_WFI_STATE,
{
.enter = ux500_enter_idle,
.exit_latency = 70,
.target_residency = 260,
.flags = CPUIDLE_FLAG_TIMER_STOP,
.name = "ApIdle",
.desc = "ARM Retention",
},
},
.safe_state_index = 0,
.state_count = 2,
};
static int dbx500_cpuidle_probe(struct platform_device *pdev)
{
/* Configure wake up reasons */
prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
PRCMU_WAKEUP(ABB));
return cpuidle_register(&ux500_idle_driver, NULL);
}
static struct platform_driver dbx500_cpuidle_plat_driver = {
.driver = {
.name = "cpuidle-dbx500",
},
.probe = dbx500_cpuidle_probe,
};
module_platform_driver(dbx500_cpuidle_plat_driver);
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