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"); 145