dm table: avoid crash if integrity profile changes (876fbba1) · Commits · 戴 / test

Commit (dm: improve block integrity support) introduced a two-phase initialization of a DM device's integrity profile. This patch avoids dereferencing a NULL 'template_disk' pointer in blk_integrity_register() if there is an integrity profile mismatch in dm_table_set_integrity(). This can occur if the integrity profiles for stacked devices in a DM table are changed between the call to dm_table_prealloc_integrity() and dm_table_set_integrity(). Reported-by:

Zdenek Kabelac <zkabelac@redhat.com> Signed-off-by:

Mike Snitzer <snitzer@redhat.com> Signed-off-by:

Alasdair G Kergon <agk@redhat.com> Cc: stable@kernel.org # 2.6.39

drivers/md/dm-table.c

+7 −6

Original line number	Original line	Diff line number	Diff line
	@@ -1238,14 +1238,15 @@ static void dm_table_set_integrity(struct dm_table *t)
	return;		return;

	template_disk = dm_table_get_integrity_disk(t, true);		template_disk = dm_table_get_integrity_disk(t, true);
	if (!template_disk &&		if (template_disk)
	blk_integrity_is_initialized(dm_disk(t->md))) {
	DMWARN("%s: device no longer has a valid integrity profile",
	dm_device_name(t->md));
	return;
	}
	blk_integrity_register(dm_disk(t->md),		blk_integrity_register(dm_disk(t->md),
	blk_get_integrity(template_disk));		blk_get_integrity(template_disk));
			else if (blk_integrity_is_initialized(dm_disk(t->md)))
			DMWARN("%s: device no longer has a valid integrity profile",
			dm_device_name(t->md));
			else
			DMWARN("%s: unable to establish an integrity profile",
			dm_device_name(t->md));
	}		}

	static int device_flush_capable(struct dm_target ti, struct dm_dev dev,		static int device_flush_capable(struct dm_target ti, struct dm_dev dev,

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