Commit 876fbba1 authored Sep 25, 2011 by Mike Snitzer Committed by Alasdair G Kergon Sep 25, 2011

dm table: avoid crash if integrity profile changes



Commit a63a5cf8 (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

parent 68e58a29

drivers/md/dm-table.c

+7 −6

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

		template_disk = dm_table_get_integrity_disk(t, true);
		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;
		}
		if (template_disk)
		blk_integrity_register(dm_disk(t->md),
		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,