Commit 8165984a authored Dec 01, 2010 by Tero Roponen Committed by Pekka Enberg Dec 04, 2010

slub: Fix a crash during slabinfo -v



Commit f7cb1933 ("SLUB: Pass active
and inactive redzone flags instead of boolean to debug functions")
missed two instances of check_object(). This caused a lot of warnings
during 'slabinfo -v' finally leading to a crash:

  BUG ext4_xattr: Freepointer corrupt
  ...
  BUG buffer_head: Freepointer corrupt
  ...
  BUG ext4_alloc_context: Freepointer corrupt
  ...
  ...
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [<ffffffff810a291f>] file_sb_list_del+0x1c/0x35
  PGD 79d78067 PUD 79e67067 PMD 0
  Oops: 0002 [#1] SMP
  last sysfs file: /sys/kernel/slab/:t-0000192/validate

This patch fixes the problem by converting the two missed instances.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tero Roponen <tero.roponen@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

parent 85beb586

mm/slub.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -3417,13 +3417,13 @@ static int validate_slab(struct kmem_cache s, struct page page,

	for_each_free_object(p, s, page->freelist) {		for_each_free_object(p, s, page->freelist) {
	set_bit(slab_index(p, s, addr), map);		set_bit(slab_index(p, s, addr), map);
	if (!check_object(s, page, p, 0))		if (!check_object(s, page, p, SLUB_RED_INACTIVE))
	return 0;		return 0;
	}		}

	for_each_object(p, s, addr, page->objects)		for_each_object(p, s, addr, page->objects)
	if (!test_bit(slab_index(p, s, addr), map))		if (!test_bit(slab_index(p, s, addr), map))
	if (!check_object(s, page, p, 1))		if (!check_object(s, page, p, SLUB_RED_ACTIVE))
	return 0;		return 0;
	return 1;		return 1;
	}		}