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be91748fa6
Hwpoison injection takes a refcount of target page and another refcount of head page of THP if the target page is the tail page of a THP. However, current code doesn't release the refcount of head page if the THP is not supported to be injected wrt hwpoison filter. Fix it by reducing the refcount of head page if the target page is the tail page of a THP and it is not supported to be injected. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
144 lines
3.3 KiB
C
144 lines
3.3 KiB
C
/* Inject a hwpoison memory failure on a arbitrary pfn */
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#include <linux/module.h>
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#include <linux/debugfs.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/pagemap.h>
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#include <linux/hugetlb.h>
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#include "internal.h"
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static struct dentry *hwpoison_dir;
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static int hwpoison_inject(void *data, u64 val)
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{
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unsigned long pfn = val;
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struct page *p;
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struct page *hpage;
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int err;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if (!pfn_valid(pfn))
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return -ENXIO;
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p = pfn_to_page(pfn);
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hpage = compound_head(p);
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/*
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* This implies unable to support free buddy pages.
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*/
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if (!get_hwpoison_page(p))
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return 0;
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if (!hwpoison_filter_enable)
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goto inject;
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if (!PageLRU(hpage) && !PageHuge(p))
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shake_page(hpage, 0);
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/*
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* This implies unable to support non-LRU pages.
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*/
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if (!PageLRU(hpage) && !PageHuge(p))
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goto put_out;
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/*
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* do a racy check with elevated page count, to make sure PG_hwpoison
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* will only be set for the targeted owner (or on a free page).
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* We temporarily take page lock for try_get_mem_cgroup_from_page().
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* memory_failure() will redo the check reliably inside page lock.
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*/
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lock_page(hpage);
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err = hwpoison_filter(hpage);
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unlock_page(hpage);
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if (err)
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goto put_out;
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inject:
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pr_info("Injecting memory failure at pfn %#lx\n", pfn);
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return memory_failure(pfn, 18, MF_COUNT_INCREASED);
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put_out:
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put_hwpoison_page(p);
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return 0;
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}
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static int hwpoison_unpoison(void *data, u64 val)
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{
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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return unpoison_memory(val);
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}
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DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
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DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
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static void pfn_inject_exit(void)
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{
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debugfs_remove_recursive(hwpoison_dir);
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}
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static int pfn_inject_init(void)
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{
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struct dentry *dentry;
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hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
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if (hwpoison_dir == NULL)
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return -ENOMEM;
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/*
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* Note that the below poison/unpoison interfaces do not involve
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* hardware status change, hence do not require hardware support.
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* They are mainly for testing hwpoison in software level.
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*/
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dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
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NULL, &hwpoison_fops);
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if (!dentry)
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goto fail;
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dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
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NULL, &unpoison_fops);
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if (!dentry)
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goto fail;
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dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
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hwpoison_dir, &hwpoison_filter_enable);
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if (!dentry)
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goto fail;
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dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
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hwpoison_dir, &hwpoison_filter_dev_major);
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if (!dentry)
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goto fail;
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dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
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hwpoison_dir, &hwpoison_filter_dev_minor);
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if (!dentry)
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goto fail;
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dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
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hwpoison_dir, &hwpoison_filter_flags_mask);
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if (!dentry)
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goto fail;
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dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
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hwpoison_dir, &hwpoison_filter_flags_value);
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if (!dentry)
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goto fail;
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#ifdef CONFIG_MEMCG_SWAP
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dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
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hwpoison_dir, &hwpoison_filter_memcg);
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if (!dentry)
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goto fail;
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#endif
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return 0;
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fail:
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pfn_inject_exit();
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return -ENOMEM;
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}
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module_init(pfn_inject_init);
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module_exit(pfn_inject_exit);
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MODULE_LICENSE("GPL");
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