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 debugfs_remove_recursive(hwpoison_dir); 76 } 77 78 static int pfn_inject_init(void) 79 { 80 struct dentry *dentry; 81 82 hwpoison_dir = debugfs_create_dir("hwpoison", NULL); 83 if (hwpoison_dir == NULL) 84 return -ENOMEM; 85 86 /* 87 * Note that the below poison/unpoison interfaces do not involve 88 * hardware status change, hence do not require hardware support. 89 * They are mainly for testing hwpoison in software level. 90 */ 91 dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, 92 NULL, &hwpoison_fops); 93 if (!dentry) 94 goto fail; 95 96 dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, 97 NULL, &unpoison_fops); 98 if (!dentry) 99 goto fail; 100 101 dentry = debugfs_create_u32("corrupt-filter-enable", 0600, 102 hwpoison_dir, &hwpoison_filter_enable); 103 if (!dentry) 104 goto fail; 105 106 dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600, 107 hwpoison_dir, &hwpoison_filter_dev_major); 108 if (!dentry) 109 goto fail; 110 111 dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600, 112 hwpoison_dir, &hwpoison_filter_dev_minor); 113 if (!dentry) 114 goto fail; 115 116 dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600, 117 hwpoison_dir, &hwpoison_filter_flags_mask); 118 if (!dentry) 119 goto fail; 120 121 dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600, 122 hwpoison_dir, &hwpoison_filter_flags_value); 123 if (!dentry) 124 goto fail; 125 126 #ifdef CONFIG_MEMCG_SWAP 127 dentry = debugfs_create_u64("corrupt-filter-memcg", 0600, 128 hwpoison_dir, &hwpoison_filter_memcg); 129 if (!dentry) 130 goto fail; 131 #endif 132 133 return 0; 134 fail: 135 pfn_inject_exit(); 136 return -ENOMEM; 137 } 138 139 module_init(pfn_inject_init); 140 module_exit(pfn_inject_exit); 141 MODULE_LICENSE("GPL"); 142