[PATCH 4.4 49/60] dm space map metadata: fix struct sm_metadata leak on failed create

From: Greg Kroah-Hartman
Date: Wed Jan 04 2017 - 16:19:48 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Benjamin Marzinski <bmarzins@xxxxxxxxxx>

commit 314c25c56c1ee5026cf99c570bdfe01847927acb upstream.

In dm_sm_metadata_create() we temporarily change the dm_space_map
operations from 'ops' (whose .destroy function deallocates the
sm_metadata) to 'bootstrap_ops' (whose .destroy function doesn't).

If dm_sm_metadata_create() fails in sm_ll_new_metadata() or
sm_ll_extend(), it exits back to dm_tm_create_internal(), which calls
dm_sm_destroy() with the intention of freeing the sm_metadata, but it
doesn't (because the dm_space_map operations is still set to
'bootstrap_ops').

Fix this by setting the dm_space_map operations back to 'ops' if
dm_sm_metadata_create() fails when it is set to 'bootstrap_ops'.

Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
Acked-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/md/persistent-data/dm-space-map-metadata.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -775,17 +775,15 @@ int dm_sm_metadata_create(struct dm_spac
memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));

r = sm_ll_new_metadata(&smm->ll, tm);
+ if (!r) {
+ if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
+ nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
+ r = sm_ll_extend(&smm->ll, nr_blocks);
+ }
+ memcpy(&smm->sm, &ops, sizeof(smm->sm));
if (r)
return r;

- if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
- nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
- r = sm_ll_extend(&smm->ll, nr_blocks);
- if (r)
- return r;
-
- memcpy(&smm->sm, &ops, sizeof(smm->sm));
-
/*
* Now we need to update the newly created data structures with the
* allocated blocks that they were built from.