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https://github.com/torvalds/linux
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8bcb74de76
shake_page() is called before going into core error handling code in
order to ensure that the error page is flushed from lru_cache lists
where pages stay during transferring among LRU lists.
But currently it's not fully functional because when the page is linked
to lru_cache by calling activate_page(), its PageLRU flag is set and
shake_page() is skipped. The result is to fail error handling with
"still referenced by 1 users" message.
When the page is linked to lru_cache by isolate_lru_page(), its PageLRU
is clear, so that's fine.
This patch makes shake_page() unconditionally called to avoild the
failure.
Fixes: 23a003bfd2 ("mm/madvise: pass return code of memory_failure() to userspace")
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Link: http://lkml.kernel.org/r/1493197841-23986-2-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Xiaolong Ye <xiaolong.ye@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
140 lines
3.2 KiB
C
140 lines
3.2 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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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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* memory_failure() will redo the check reliably inside page lock.
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*/
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err = hwpoison_filter(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
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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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