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(hpage) && !PageHuge(p))
  38                 shake_page(hpage, 0);
  39         /*
  40          * This implies unable to support non-LRU pages.
  41          */
  42         if (!PageLRU(hpage) && !PageHuge(p))
  43                 goto put_out;
  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                 goto put_out;
  56
  57 inject:
  58         pr_info("Injecting memory failure at pfn %#lx\n", pfn);
  59         return memory_failure(pfn, 18, MF_COUNT_INCREASED);
  60 put_out:
  61         put_page(hpage);
  62         return 0;
  63 }
  64
  65 static int hwpoison_unpoison(void *data, u64 val)
  66 {
  67         if (!capable(CAP_SYS_ADMIN))
  68                 return -EPERM;
  69
  70         return unpoison_memory(val);
  71 }
  72
  73 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
  74 DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
  75
  76 static void pfn_inject_exit(void)
  77 {
  78         debugfs_remove_recursive(hwpoison_dir);
  79 }
  80
  81 static int pfn_inject_init(void)
  82 {
  83         struct dentry *dentry;
  84
  85         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
  86         if (hwpoison_dir == NULL)
  87                 return -ENOMEM;
  88
  89         /*
  90          * Note that the below poison/unpoison interfaces do not involve
  91          * hardware status change, hence do not require hardware support.
  92          * They are mainly for testing hwpoison in software level.
  93          */
  94         dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
  95                                           NULL, &hwpoison_fops);
  96         if (!dentry)
  97                 goto fail;
  98
  99         dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
 100                                      NULL, &unpoison_fops);
 101         if (!dentry)
 102                 goto fail;
 103
 104         dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
 105                                     hwpoison_dir, &hwpoison_filter_enable);
 106         if (!dentry)
 107                 goto fail;
 108
 109         dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
 110                                     hwpoison_dir, &hwpoison_filter_dev_major);
 111         if (!dentry)
 112                 goto fail;
 113
 114         dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
 115                                     hwpoison_dir, &hwpoison_filter_dev_minor);
 116         if (!dentry)
 117                 goto fail;
 118
 119         dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
 120                                     hwpoison_dir, &hwpoison_filter_flags_mask);
 121         if (!dentry)
 122                 goto fail;
 123
 124         dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
 125                                     hwpoison_dir, &hwpoison_filter_flags_value);
 126         if (!dentry)
 127                 goto fail;
 128
 129 #ifdef CONFIG_MEMCG_SWAP
 130         dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
 131                                     hwpoison_dir, &hwpoison_filter_memcg);
 132         if (!dentry)
 133                 goto fail;
 134 #endif
 135
 136         return 0;
 137 fail:
 138         pfn_inject_exit();
 139         return -ENOMEM;
 140 }
 141
 142 module_init(pfn_inject_init);
 143 module_exit(pfn_inject_exit);
 144 MODULE_LICENSE("GPL");