Commit a82f7119 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Len Brown
Browse files

Hibernation: Fix mark_nosave_pages() 

There is a problem in the hibernation code that triggers on some NUMA
systems on which pfn_valid() returns 'true' for some PFNs that don't
belong to any zone.  Namely, there is a BUG_ON() in
memory_bm_find_bit() that triggers for PFNs not belonging to any
zone and passing the pfn_valid() test.  On the affected systems it
triggers when we mark PFNs reported by the platform as not saveable,
because the PFNs in question belong to a region mapped directly using
iorepam() (i.e. the ACPI data area) and they pass the pfn_valid()
test.

Modify memory_bm_find_bit() so that it returns an error if given PFN
doesn't belong to any zone instead of crashing the kernel and ignore
the result returned by it in mark_nosave_pages(), while marking the
"nosave" memory regions.

This doesn't affect the hibernation functionality, as we won't touch
the PFNs in question anyway.

http://bugzilla.kernel.org/show_bug.cgi?id=9966

 .

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent baadac8b

kernel/power/snapshot.c

+34 −7
Original line number Diff line number Diff line
@@ -447,7 +447,7 @@ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free) 
 *	of @bm->cur_zone_bm are updated.

 */



static void memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,

static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,

				void **addr, unsigned int *bit_nr)

{

	struct zone_bitmap *zone_bm;
@@ -461,7 +461,8 @@ static void memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, 
		while (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {

			zone_bm = zone_bm->next;



			BUG_ON(!zone_bm);

			if (!zone_bm)

				return -EFAULT;

		}

		bm->cur.zone_bm = zone_bm;

	}
@@ -479,23 +480,40 @@ static void memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, 
	pfn -= bb->start_pfn;

	*bit_nr = pfn % BM_BITS_PER_CHUNK;

	*addr = bb->data + pfn / BM_BITS_PER_CHUNK;

	return 0;

}



static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)

{

	void *addr;

	unsigned int bit;

	int error;



	memory_bm_find_bit(bm, pfn, &addr, &bit);

	error = memory_bm_find_bit(bm, pfn, &addr, &bit);

	BUG_ON(error);

	set_bit(bit, addr);

}



static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)

{

	void *addr;

	unsigned int bit;

	int error;



	error = memory_bm_find_bit(bm, pfn, &addr, &bit);

	if (!error)

		set_bit(bit, addr);

	return error;

}



static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)

{

	void *addr;

	unsigned int bit;

	int error;



	memory_bm_find_bit(bm, pfn, &addr, &bit);

	error = memory_bm_find_bit(bm, pfn, &addr, &bit);

	BUG_ON(error);

	clear_bit(bit, addr);

}
@@ -503,8 +521,10 @@ static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn) 
{

	void *addr;

	unsigned int bit;

	int error;



	memory_bm_find_bit(bm, pfn, &addr, &bit);

	error = memory_bm_find_bit(bm, pfn, &addr, &bit);

	BUG_ON(error);

	return test_bit(bit, addr);

}
@@ -709,8 +729,15 @@ static void mark_nosave_pages(struct memory_bitmap *bm) 
				region->end_pfn << PAGE_SHIFT);



		for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)

			if (pfn_valid(pfn))

				memory_bm_set_bit(bm, pfn);

			if (pfn_valid(pfn)) {

				/*

				 * It is safe to ignore the result of

				 * mem_bm_set_bit_check() here, since we won't

				 * touch the PFNs for which the error is

				 * returned anyway.

				 */

				mem_bm_set_bit_check(bm, pfn);

			}

	}

}

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