mm/hwpoison-inject.c

   1 /* Inject a hwpoison memory failure on a arbitrary 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 <linux/hugetlb.h>
   9 #include "internal.h"
  10
  11 static struct dentry *hwpoison_dir;
  12
  13 static int hwpoison_inject(void *data, u64 val)
  14 {
  15         unsigned long pfn = val;
  16         struct page *p;
  17         struct page *hpage;
  18         int err;
  19
  20         if (!capable(CAP_SYS_ADMIN))
  21                 return -EPERM;
  22
  23         if (!pfn_valid(pfn))
  24                 return -ENXIO;
  25
  26         p = pfn_to_page(pfn);
  27         hpage = compound_head(p);
  28         /*
  29          * This implies unable to support free buddy pages.
  30          */
  31         if (!get_page_unless_zero(hpage))
  32                 return 0;
  33
  34         if (!hwpoison_filter_enable)
  35                 goto inject;
  36
  37         if (!PageLRU(p) && !PageHuge(p))
  38                 shake_page(p, 0);
  39         /*
  40          * This implies unable to support non-LRU pages.
  41          */
  42         if (!PageLRU(p) && !PageHuge(p))
  43                 return 0;
  44
  45         /*
  46          * do a racy check with elevated page count, to make sure PG_hwpoison
  47          * will only be set for the targeted owner (or on a free page).
  48          * We temporarily take page lock for try_get_mem_cgroup_from_page().
  49          * memory_failure() will redo the check reliably inside page lock.
  50          */
  51         lock_page(hpage);
  52         err = hwpoison_filter(hpage);
  53         unlock_page(hpage);
  54         if (err)
  55                 return 0;
  56
  57 inject:
  58         pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  59         return memory_failure(pfn, 18, MF_COUNT_INCREASED);
  60 }
  61
  62 static int hwpoison_unpoison(void *data, u64 val)
  63 {
  64         if (!capable(CAP_SYS_ADMIN))
  65                 return -EPERM;
  66
  67         return unpoison_memory(val);
  68 }
  69
  70 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  71 DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  72
  73 static void pfn_inject_exit(void)
  74 {
  75         if (hwpoison_dir)
  76                 debugfs_remove_recursive(hwpoison_dir);
  77 }
  78
  79 static int pfn_inject_init(void)
  80 {
  81         struct dentry *dentry;
  82
  83         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  84         if (hwpoison_dir == NULL)
  85                 return -ENOMEM;
  86
  87         /*
  88          * Note that the below poison/unpoison interfaces do not involve
  89          * hardware status change, hence do not require hardware support.
  90          * They are mainly for testing hwpoison in software level.
  91          */
  92         dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
  93                                           NULL, &hwpoison_fops);
  94         if (!dentry)
  95                 goto fail;
  96
  97         dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
  98                                      NULL, &unpoison_fops);
  99         if (!dentry)
 100                 goto fail;
 101
 102         dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
 103                                     hwpoison_dir, &hwpoison_filter_enable);
 104         if (!dentry)
 105                 goto fail;
 106
 107         dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
 108                                     hwpoison_dir, &hwpoison_filter_dev_major);
 109         if (!dentry)
 110                 goto fail;
 111
 112         dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
 113                                     hwpoison_dir, &hwpoison_filter_dev_minor);
 114         if (!dentry)
 115                 goto fail;
 116
 117         dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
 118                                     hwpoison_dir, &hwpoison_filter_flags_mask);
 119         if (!dentry)
 120                 goto fail;
 121
 122         dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
 123                                     hwpoison_dir, &hwpoison_filter_flags_value);
 124         if (!dentry)
 125                 goto fail;
 126
 127 #ifdef CONFIG_MEMCG_SWAP
 128         dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
 129                                     hwpoison_dir, &hwpoison_filter_memcg);
 130         if (!dentry)
 131                 goto fail;
 132 #endif
 133
 134         return 0;
 135 fail:
 136         pfn_inject_exit();
 137         return -ENOMEM;
 138 }
 139
 140 module_init(pfn_inject_init);
 141 module_exit(pfn_inject_exit);
 142 MODULE_LICENSE("GPL");