fb31ba30fb
The lack of one reference count against poisoned page for hwpoison_inject w/o hwpoison_filter enabled result in hwpoison detect -1 users still referenced the page, however, the number should be 0 except the poison handler held one after successfully unmap. This patch fix it by hold one referenced count against poisoned page for hwpoison_inject w/ and w/o hwpoison_filter enabled. Before patch: [ 71.902112] Injecting memory failure at pfn 224706 [ 71.902137] MCE 0x224706: dirty LRU page recovery: Failed [ 71.902138] MCE 0x224706: dirty LRU page still referenced by -1 users After patch: [ 94.710860] Injecting memory failure at pfn 215b68 [ 94.710885] MCE 0x215b68: dirty LRU page recovery: Recovered Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
142 lines
3.3 KiB
C
142 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_page_unless_zero(hpage))
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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(p) && !PageHuge(p))
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shake_page(p, 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(p) && !PageHuge(p))
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return 0;
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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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return 0;
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inject:
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printk(KERN_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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}
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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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if (hwpoison_dir)
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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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