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Commit 7c116f2b authored by Wu Fengguang's avatar Wu Fengguang Committed by Andi Kleen
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HWPOISON: add fs/device filters 



Filesystem data/metadata present the most tricky-to-isolate pages.
It requires careful code review and stress testing to get them right.

The fs/device filter helps to target the stress tests to some specific
filesystem pages. The filter condition is block device's major/minor
numbers:
        - corrupt-filter-dev-major
        - corrupt-filter-dev-minor
When specified (non -1), only page cache pages that belong to that
device will be poisoned.

The filters are checked reliably on the locked and refcounted page.

Haicheng: clear PG_hwpoison and drop bad page count if filter not OK
AK: Add documentation

CC: Haicheng Li <haicheng.li@intel.com>
CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
parent 138ce286

Documentation/vm/hwpoison.txt

+7 −0
Original line number Diff line number Diff line
@@ -115,6 +115,13 @@ memory failures. 
Note these injection interfaces are not stable and might change between

kernel versions



corrupt-filter-dev-major

corrupt-filter-dev-minor



Only handle memory failures to pages associated with the file system defined

by block device major/minor.  -1U is the wildcard value.

This should be only used for testing with artificial injection.



Architecture specific MCE injector



x86 has mce-inject, mce-test

mm/hwpoison-inject.c

+11 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#include <linux/debugfs.h>

#include <linux/kernel.h>

#include <linux/mm.h>

#include "internal.h"



static struct dentry *hwpoison_dir;
@@ -54,6 +55,16 @@ static int pfn_inject_init(void) 
	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;



	return 0;

fail:

	pfn_inject_exit();

mm/internal.h

+3 −0
Original line number Diff line number Diff line
@@ -250,3 +250,6 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
#define ZONE_RECLAIM_SOME	0

#define ZONE_RECLAIM_SUCCESS	1

#endif



extern u32 hwpoison_filter_dev_major;

extern u32 hwpoison_filter_dev_minor;

mm/memory-failure.c

+51 −0
Original line number Diff line number Diff line
@@ -48,6 +48,50 @@ int sysctl_memory_failure_recovery __read_mostly = 1; 


atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);



u32 hwpoison_filter_dev_major = ~0U;

u32 hwpoison_filter_dev_minor = ~0U;

EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);

EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);



static int hwpoison_filter_dev(struct page *p)

{

	struct address_space *mapping;

	dev_t dev;



	if (hwpoison_filter_dev_major == ~0U &&

	    hwpoison_filter_dev_minor == ~0U)

		return 0;



	/*

	 * page_mapping() does not accept slab page

	 */

	if (PageSlab(p))

		return -EINVAL;



	mapping = page_mapping(p);

	if (mapping == NULL || mapping->host == NULL)

		return -EINVAL;



	dev = mapping->host->i_sb->s_dev;

	if (hwpoison_filter_dev_major != ~0U &&

	    hwpoison_filter_dev_major != MAJOR(dev))

		return -EINVAL;

	if (hwpoison_filter_dev_minor != ~0U &&

	    hwpoison_filter_dev_minor != MINOR(dev))

		return -EINVAL;



	return 0;

}



int hwpoison_filter(struct page *p)

{

	if (hwpoison_filter_dev(p))

		return -EINVAL;



	return 0;

}

EXPORT_SYMBOL_GPL(hwpoison_filter);



/*

 * Send all the processes who have the page mapped an ``action optional''

 * signal.
@@ -843,6 +887,13 @@ int __memory_failure(unsigned long pfn, int trapno, int flags) 
		res = 0;

		goto out;

	}

	if (hwpoison_filter(p)) {

		if (TestClearPageHWPoison(p))

			atomic_long_dec(&mce_bad_pages);

		unlock_page(p);

		put_page(p);

		return 0;

	}



	wait_on_page_writeback(p);