Revision 7d638093d4b0e9ef15bd78f38f11f126e773cc14 authored by Vladimir Davydov on 10 June 2015, 18:14:46 UTC, committed by Linus Torvalds on 10 June 2015, 23:43:43 UTC
When trimming memcg consumption excess (see memory.high), we call try_to_free_mem_cgroup_pages without checking if we are allowed to sleep in the current context, which can result in a deadlock. Fix this. Fixes: 241994ed8649 ("mm: memcontrol: default hierarchy interface for memory") Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 85bd839
test_firmware.c
/*
* This module provides an interface to trigger and test firmware loading.
*
* It is designed to be used for basic evaluation of the firmware loading
* subsystem (for example when validating firmware verification). It lacks
* any extra dependencies, and will not normally be loaded by the system
* unless explicitly requested by name.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/firmware.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
static DEFINE_MUTEX(test_fw_mutex);
static const struct firmware *test_firmware;
static ssize_t test_fw_misc_read(struct file *f, char __user *buf,
size_t size, loff_t *offset)
{
ssize_t rc = 0;
mutex_lock(&test_fw_mutex);
if (test_firmware)
rc = simple_read_from_buffer(buf, size, offset,
test_firmware->data,
test_firmware->size);
mutex_unlock(&test_fw_mutex);
return rc;
}
static const struct file_operations test_fw_fops = {
.owner = THIS_MODULE,
.read = test_fw_misc_read,
};
static struct miscdevice test_fw_misc_device = {
.minor = MISC_DYNAMIC_MINOR,
.name = "test_firmware",
.fops = &test_fw_fops,
};
static ssize_t trigger_request_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
int rc;
char *name;
name = kzalloc(count + 1, GFP_KERNEL);
if (!name)
return -ENOSPC;
memcpy(name, buf, count);
pr_info("loading '%s'\n", name);
mutex_lock(&test_fw_mutex);
release_firmware(test_firmware);
test_firmware = NULL;
rc = request_firmware(&test_firmware, name, dev);
if (rc)
pr_info("load of '%s' failed: %d\n", name, rc);
pr_info("loaded: %zu\n", test_firmware ? test_firmware->size : 0);
mutex_unlock(&test_fw_mutex);
kfree(name);
return count;
}
static DEVICE_ATTR_WO(trigger_request);
static int __init test_firmware_init(void)
{
int rc;
rc = misc_register(&test_fw_misc_device);
if (rc) {
pr_err("could not register misc device: %d\n", rc);
return rc;
}
rc = device_create_file(test_fw_misc_device.this_device,
&dev_attr_trigger_request);
if (rc) {
pr_err("could not create sysfs interface: %d\n", rc);
goto dereg;
}
pr_warn("interface ready\n");
return 0;
dereg:
misc_deregister(&test_fw_misc_device);
return rc;
}
module_init(test_firmware_init);
static void __exit test_firmware_exit(void)
{
release_firmware(test_firmware);
device_remove_file(test_fw_misc_device.this_device,
&dev_attr_trigger_request);
misc_deregister(&test_fw_misc_device);
pr_warn("removed interface\n");
}
module_exit(test_firmware_exit);
MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
MODULE_LICENSE("GPL");
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