/* Inject a hwpoison memory failure on a arbitrary pfn */ #include <linux/module.h> #include <linux/debugfs.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/swap.h> #include <linux/pagemap.h> #include <linux/hugetlb.h> #include "internal.h" static struct dentry *hwpoison_dir; static int hwpoison_inject(void *data, u64 val) { unsigned long pfn = val; struct page *p; struct page *hpage; int err; if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (!pfn_valid(pfn)) return -ENXIO; p = pfn_to_page(pfn); hpage = compound_head(p); /* * This implies unable to support free buddy pages. */ if (!get_page_unless_zero(hpage)) return 0; if (!hwpoison_filter_enable) goto inject; if (!PageLRU(p) && !PageHuge(p)) shake_page(p, 0); /* * This implies unable to support non-LRU pages. */ if (!PageLRU(p) && !PageHuge(p)) return 0; /* * do a racy check with elevated page count, to make sure PG_hwpoison * will only be set for the targeted owner (or on a free page). * We temporarily take page lock for try_get_mem_cgroup_from_page(). * memory_failure() will redo the check reliably inside page lock. */ lock_page(hpage); err = hwpoison_filter(hpage); unlock_page(hpage); if (err) return 0; inject: pr_info("Injecting memory failure at pfn %#lx\n", pfn); return memory_failure(pfn, 18, MF_COUNT_INCREASED); } static int hwpoison_unpoison(void *data, u64 val) { if (!capable(CAP_SYS_ADMIN)) return -EPERM; return unpoison_memory(val); } DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n"); DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n"); static void pfn_inject_exit(void) { debugfs_remove_recursive(hwpoison_dir); } static int pfn_inject_init(void) { struct dentry *dentry; hwpoison_dir = debugfs_create_dir("hwpoison", NULL); if (hwpoison_dir == NULL) return -ENOMEM; /* * Note that the below poison/unpoison interfaces do not involve * hardware status change, hence do not require hardware support. * They are mainly for testing hwpoison in software level. */ dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL, &hwpoison_fops); if (!dentry) goto fail; dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL, &unpoison_fops); if (!dentry) goto fail; dentry = debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir, &hwpoison_filter_enable); if (!dentry) goto fail; dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir, &hwpoison_filter_dev_major); if (!dentry) goto fail; dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir, &hwpoison_filter_dev_minor); if (!dentry) goto fail; dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir, &hwpoison_filter_flags_mask); if (!dentry) goto fail; dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir, &hwpoison_filter_flags_value); if (!dentry) goto fail; #ifdef CONFIG_MEMCG_SWAP dentry = debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir, &hwpoison_filter_memcg); if (!dentry) goto fail; #endif return 0; fail: pfn_inject_exit(); return -ENOMEM; } module_init(pfn_inject_init); module_exit(pfn_inject_exit); MODULE_LICENSE("GPL");