Root/mm/hwpoison-inject.c

1/* Inject a hwpoison memory failure on a arbitary pfn */
2#include <linux/module.h>
3#include <linux/debugfs.h>
4#include <linux/kernel.h>
5#include <linux/mm.h>
6#include <linux/swap.h>
7#include <linux/pagemap.h>
8#include "internal.h"
9
10static struct dentry *hwpoison_dir;
11
12static int hwpoison_inject(void *data, u64 val)
13{
14    unsigned long pfn = val;
15    struct page *p;
16    int err;
17
18    if (!capable(CAP_SYS_ADMIN))
19        return -EPERM;
20
21    if (!hwpoison_filter_enable)
22        goto inject;
23    if (!pfn_valid(pfn))
24        return -ENXIO;
25
26    p = pfn_to_page(pfn);
27    /*
28     * This implies unable to support free buddy pages.
29     */
30    if (!get_page_unless_zero(p))
31        return 0;
32
33    if (!PageLRU(p))
34        shake_page(p, 0);
35    /*
36     * This implies unable to support non-LRU pages.
37     */
38    if (!PageLRU(p))
39        return 0;
40
41    /*
42     * do a racy check with elevated page count, to make sure PG_hwpoison
43     * will only be set for the targeted owner (or on a free page).
44     * We temporarily take page lock for try_get_mem_cgroup_from_page().
45     * __memory_failure() will redo the check reliably inside page lock.
46     */
47    lock_page(p);
48    err = hwpoison_filter(p);
49    unlock_page(p);
50    if (err)
51        return 0;
52
53inject:
54    printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
55    return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
56}
57
58static int hwpoison_unpoison(void *data, u64 val)
59{
60    if (!capable(CAP_SYS_ADMIN))
61        return -EPERM;
62
63    return unpoison_memory(val);
64}
65
66DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
67DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
68
69static void pfn_inject_exit(void)
70{
71    if (hwpoison_dir)
72        debugfs_remove_recursive(hwpoison_dir);
73}
74
75static int pfn_inject_init(void)
76{
77    struct dentry *dentry;
78
79    hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
80    if (hwpoison_dir == NULL)
81        return -ENOMEM;
82
83    /*
84     * Note that the below poison/unpoison interfaces do not involve
85     * hardware status change, hence do not require hardware support.
86     * They are mainly for testing hwpoison in software level.
87     */
88    dentry = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
89                      NULL, &hwpoison_fops);
90    if (!dentry)
91        goto fail;
92
93    dentry = debugfs_create_file("unpoison-pfn", 0600, hwpoison_dir,
94                     NULL, &unpoison_fops);
95    if (!dentry)
96        goto fail;
97
98    dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
99                    hwpoison_dir, &hwpoison_filter_enable);
100    if (!dentry)
101        goto fail;
102
103    dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
104                    hwpoison_dir, &hwpoison_filter_dev_major);
105    if (!dentry)
106        goto fail;
107
108    dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
109                    hwpoison_dir, &hwpoison_filter_dev_minor);
110    if (!dentry)
111        goto fail;
112
113    dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
114                    hwpoison_dir, &hwpoison_filter_flags_mask);
115    if (!dentry)
116        goto fail;
117
118    dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
119                    hwpoison_dir, &hwpoison_filter_flags_value);
120    if (!dentry)
121        goto fail;
122
123#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
124    dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
125                    hwpoison_dir, &hwpoison_filter_memcg);
126    if (!dentry)
127        goto fail;
128#endif
129
130    return 0;
131fail:
132    pfn_inject_exit();
133    return -ENOMEM;
134}
135
136module_init(pfn_inject_init);
137module_exit(pfn_inject_exit);
138MODULE_LICENSE("GPL");
139

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