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linux-next/kernel/power/user.c
Rafael J. Wysocki c9e664f1fd PM / Hibernate: Fix memory corruption related to swap
There is a problem that swap pages allocated before the creation of
a hibernation image can be released and used for storing the contents
of different memory pages while the image is being saved.  Since the
kernel stored in the image doesn't know of that, it causes memory
corruption to occur after resume from hibernation, especially on
systems with relatively small RAM that need to swap often.

This issue can be addressed by keeping the GFP_IOFS bits clear
in gfp_allowed_mask during the entire hibernation, including the
saving of the image, until the system is finally turned off or
the hibernation is aborted.  Unfortunately, for this purpose
it's necessary to rework the way in which the hibernate and
suspend code manipulates gfp_allowed_mask.

This change is based on an earlier patch from Hugh Dickins.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Ondrej Zary <linux@rainbow-software.org>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: stable@kernel.org
2010-12-06 23:52:08 +01:00

482 lines
10 KiB
C

/*
* linux/kernel/power/user.c
*
* This file provides the user space interface for software suspend/resume.
*
* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
*
* This file is released under the GPLv2.
*
*/
#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/pm.h>
#include <linux/fs.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <scsi/scsi_scan.h>
#include <asm/uaccess.h>
#include "power.h"
/*
* NOTE: The SNAPSHOT_SET_SWAP_FILE and SNAPSHOT_PMOPS ioctls are obsolete and
* will be removed in the future. They are only preserved here for
* compatibility with existing userland utilities.
*/
#define SNAPSHOT_SET_SWAP_FILE _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
#define SNAPSHOT_PMOPS _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
#define PMOPS_PREPARE 1
#define PMOPS_ENTER 2
#define PMOPS_FINISH 3
/*
* NOTE: The following ioctl definitions are wrong and have been replaced with
* correct ones. They are only preserved here for compatibility with existing
* userland utilities and will be removed in the future.
*/
#define SNAPSHOT_ATOMIC_SNAPSHOT _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
#define SNAPSHOT_SET_IMAGE_SIZE _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
#define SNAPSHOT_AVAIL_SWAP _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
#define SNAPSHOT_GET_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
#define SNAPSHOT_MINOR 231
static struct snapshot_data {
struct snapshot_handle handle;
int swap;
int mode;
char frozen;
char ready;
char platform_support;
} snapshot_state;
atomic_t snapshot_device_available = ATOMIC_INIT(1);
static int snapshot_open(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
int error;
mutex_lock(&pm_mutex);
if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
error = -EBUSY;
goto Unlock;
}
if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
atomic_inc(&snapshot_device_available);
error = -ENOSYS;
goto Unlock;
}
if(create_basic_memory_bitmaps()) {
atomic_inc(&snapshot_device_available);
error = -ENOMEM;
goto Unlock;
}
nonseekable_open(inode, filp);
data = &snapshot_state;
filp->private_data = data;
memset(&data->handle, 0, sizeof(struct snapshot_handle));
if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
/* Hibernating. The image device should be accessible. */
data->swap = swsusp_resume_device ?
swap_type_of(swsusp_resume_device, 0, NULL) : -1;
data->mode = O_RDONLY;
error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
if (error)
pm_notifier_call_chain(PM_POST_HIBERNATION);
} else {
/*
* Resuming. We may need to wait for the image device to
* appear.
*/
wait_for_device_probe();
scsi_complete_async_scans();
data->swap = -1;
data->mode = O_WRONLY;
error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
if (error)
pm_notifier_call_chain(PM_POST_RESTORE);
}
if (error)
atomic_inc(&snapshot_device_available);
data->frozen = 0;
data->ready = 0;
data->platform_support = 0;
Unlock:
mutex_unlock(&pm_mutex);
return error;
}
static int snapshot_release(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
mutex_lock(&pm_mutex);
swsusp_free();
free_basic_memory_bitmaps();
data = filp->private_data;
free_all_swap_pages(data->swap);
if (data->frozen)
thaw_processes();
pm_notifier_call_chain(data->mode == O_WRONLY ?
PM_POST_HIBERNATION : PM_POST_RESTORE);
atomic_inc(&snapshot_device_available);
mutex_unlock(&pm_mutex);
return 0;
}
static ssize_t snapshot_read(struct file *filp, char __user *buf,
size_t count, loff_t *offp)
{
struct snapshot_data *data;
ssize_t res;
loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
data = filp->private_data;
if (!data->ready) {
res = -ENODATA;
goto Unlock;
}
if (!pg_offp) { /* on page boundary? */
res = snapshot_read_next(&data->handle);
if (res <= 0)
goto Unlock;
} else {
res = PAGE_SIZE - pg_offp;
}
res = simple_read_from_buffer(buf, count, &pg_offp,
data_of(data->handle), res);
if (res > 0)
*offp += res;
Unlock:
mutex_unlock(&pm_mutex);
return res;
}
static ssize_t snapshot_write(struct file *filp, const char __user *buf,
size_t count, loff_t *offp)
{
struct snapshot_data *data;
ssize_t res;
loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
data = filp->private_data;
if (!pg_offp) {
res = snapshot_write_next(&data->handle);
if (res <= 0)
goto unlock;
} else {
res = PAGE_SIZE - pg_offp;
}
res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
buf, count);
if (res > 0)
*offp += res;
unlock:
mutex_unlock(&pm_mutex);
return res;
}
static void snapshot_deprecated_ioctl(unsigned int cmd)
{
if (printk_ratelimit())
printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will "
"be removed soon, update your suspend-to-disk "
"utilities\n",
__builtin_return_address(0), cmd);
}
static long snapshot_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
int error = 0;
struct snapshot_data *data;
loff_t size;
sector_t offset;
if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
return -ENOTTY;
if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
return -ENOTTY;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!mutex_trylock(&pm_mutex))
return -EBUSY;
data = filp->private_data;
switch (cmd) {
case SNAPSHOT_FREEZE:
if (data->frozen)
break;
printk("Syncing filesystems ... ");
sys_sync();
printk("done.\n");
error = usermodehelper_disable();
if (error)
break;
error = freeze_processes();
if (error) {
thaw_processes();
usermodehelper_enable();
}
if (!error)
data->frozen = 1;
break;
case SNAPSHOT_UNFREEZE:
if (!data->frozen || data->ready)
break;
pm_restore_gfp_mask();
thaw_processes();
usermodehelper_enable();
data->frozen = 0;
break;
case SNAPSHOT_ATOMIC_SNAPSHOT:
snapshot_deprecated_ioctl(cmd);
case SNAPSHOT_CREATE_IMAGE:
if (data->mode != O_RDONLY || !data->frozen || data->ready) {
error = -EPERM;
break;
}
pm_restore_gfp_mask();
error = hibernation_snapshot(data->platform_support);
if (!error)
error = put_user(in_suspend, (int __user *)arg);
if (!error)
data->ready = 1;
break;
case SNAPSHOT_ATOMIC_RESTORE:
snapshot_write_finalize(&data->handle);
if (data->mode != O_WRONLY || !data->frozen ||
!snapshot_image_loaded(&data->handle)) {
error = -EPERM;
break;
}
error = hibernation_restore(data->platform_support);
break;
case SNAPSHOT_FREE:
swsusp_free();
memset(&data->handle, 0, sizeof(struct snapshot_handle));
data->ready = 0;
break;
case SNAPSHOT_SET_IMAGE_SIZE:
snapshot_deprecated_ioctl(cmd);
case SNAPSHOT_PREF_IMAGE_SIZE:
image_size = arg;
break;
case SNAPSHOT_GET_IMAGE_SIZE:
if (!data->ready) {
error = -ENODATA;
break;
}
size = snapshot_get_image_size();
size <<= PAGE_SHIFT;
error = put_user(size, (loff_t __user *)arg);
break;
case SNAPSHOT_AVAIL_SWAP:
snapshot_deprecated_ioctl(cmd);
case SNAPSHOT_AVAIL_SWAP_SIZE:
size = count_swap_pages(data->swap, 1);
size <<= PAGE_SHIFT;
error = put_user(size, (loff_t __user *)arg);
break;
case SNAPSHOT_GET_SWAP_PAGE:
snapshot_deprecated_ioctl(cmd);
case SNAPSHOT_ALLOC_SWAP_PAGE:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
break;
}
offset = alloc_swapdev_block(data->swap);
if (offset) {
offset <<= PAGE_SHIFT;
error = put_user(offset, (loff_t __user *)arg);
} else {
error = -ENOSPC;
}
break;
case SNAPSHOT_FREE_SWAP_PAGES:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
break;
}
free_all_swap_pages(data->swap);
break;
case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */
snapshot_deprecated_ioctl(cmd);
if (!swsusp_swap_in_use()) {
/*
* User space encodes device types as two-byte values,
* so we need to recode them
*/
if (old_decode_dev(arg)) {
data->swap = swap_type_of(old_decode_dev(arg),
0, NULL);
if (data->swap < 0)
error = -ENODEV;
} else {
data->swap = -1;
error = -EINVAL;
}
} else {
error = -EPERM;
}
break;
case SNAPSHOT_S2RAM:
if (!data->frozen) {
error = -EPERM;
break;
}
/*
* Tasks are frozen and the notifiers have been called with
* PM_HIBERNATION_PREPARE
*/
error = suspend_devices_and_enter(PM_SUSPEND_MEM);
break;
case SNAPSHOT_PLATFORM_SUPPORT:
data->platform_support = !!arg;
break;
case SNAPSHOT_POWER_OFF:
if (data->platform_support)
error = hibernation_platform_enter();
break;
case SNAPSHOT_PMOPS: /* This ioctl is deprecated */
snapshot_deprecated_ioctl(cmd);
error = -EINVAL;
switch (arg) {
case PMOPS_PREPARE:
data->platform_support = 1;
error = 0;
break;
case PMOPS_ENTER:
if (data->platform_support)
error = hibernation_platform_enter();
break;
case PMOPS_FINISH:
if (data->platform_support)
error = 0;
break;
default:
printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
}
break;
case SNAPSHOT_SET_SWAP_AREA:
if (swsusp_swap_in_use()) {
error = -EPERM;
} else {
struct resume_swap_area swap_area;
dev_t swdev;
error = copy_from_user(&swap_area, (void __user *)arg,
sizeof(struct resume_swap_area));
if (error) {
error = -EFAULT;
break;
}
/*
* User space encodes device types as two-byte values,
* so we need to recode them
*/
swdev = new_decode_dev(swap_area.dev);
if (swdev) {
offset = swap_area.offset;
data->swap = swap_type_of(swdev, offset, NULL);
if (data->swap < 0)
error = -ENODEV;
} else {
data->swap = -1;
error = -EINVAL;
}
}
break;
default:
error = -ENOTTY;
}
mutex_unlock(&pm_mutex);
return error;
}
static const struct file_operations snapshot_fops = {
.open = snapshot_open,
.release = snapshot_release,
.read = snapshot_read,
.write = snapshot_write,
.llseek = no_llseek,
.unlocked_ioctl = snapshot_ioctl,
};
static struct miscdevice snapshot_device = {
.minor = SNAPSHOT_MINOR,
.name = "snapshot",
.fops = &snapshot_fops,
};
static int __init snapshot_device_init(void)
{
return misc_register(&snapshot_device);
};
device_initcall(snapshot_device_init);