// SPDX-License-Identifier: GPL-2.0-only /* 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_hwpoison_page(p)) return 0; if (!hwpoison_filter_enable) goto inject; shake_page(hpage, 0); /* * This implies unable to support non-LRU pages. */ if (!PageLRU(hpage) && !PageHuge(p)) goto put_out; /* * 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). * memory_failure() will redo the check reliably inside page lock. */ err = hwpoison_filter(hpage); if (err) goto put_out; inject: pr_info("Injecting memory failure at pfn %#lx\n", pfn); return memory_failure(pfn, MF_COUNT_INCREASED); put_out: put_hwpoison_page(p); return 0; } 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) { hwpoison_dir = debugfs_create_dir("hwpoison", NULL); /* * 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. */ debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL, &hwpoison_fops); debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL, &unpoison_fops); debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir, &hwpoison_filter_enable); debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir, &hwpoison_filter_dev_major); debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir, &hwpoison_filter_dev_minor); debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir, &hwpoison_filter_flags_mask); debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir, &hwpoison_filter_flags_value); #ifdef CONFIG_MEMCG debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir, &hwpoison_filter_memcg); #endif return 0; } module_init(pfn_inject_init); module_exit(pfn_inject_exit); MODULE_LICENSE("GPL");