[ 134/187] dm persistent data: handle space map checker creation failure

Greg Kroah-Hartman
2012-07-12T22:43:35Z

From: Mike Snitzer <snitzer@redhat.com>

commit 62662303e7f590fdfbb0070ab820a0ad4267c119 upstream.

If CONFIG_DM_DEBUG_SPACE_MAPS is enabled and dm_sm_checker_create()
fails, dm_tm_create_internal() would still return success even though it
cleaned up all resources it was supposed to have created. This will
lead to a kernel crash:

general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
...
RIP: 0010:[<ffffffff81593659>] [<ffffffff81593659>] dm_bufio_get_block_size+0x9/0x20
Call Trace:
[<ffffffff81599bae>] dm_bm_block_size+0xe/0x10
[<ffffffff8159b8b8>] sm_ll_init+0x78/0xd0
[<ffffffff8159c1a6>] sm_ll_new_disk+0x16/0xa0
[<ffffffff8159c98e>] dm_sm_disk_create+0xfe/0x160
[<ffffffff815abf6e>] dm_pool_metadata_open+0x16e/0x6a0
[<ffffffff815aa010>] pool_ctr+0x3f0/0x900
[<ffffffff8158d565>] dm_table_add_target+0x195/0x450
[<ffffffff815904c4>] table_load+0xe4/0x330
[<ffffffff815917ea>] ctl_ioctl+0x15a/0x2c0
[<ffffffff81591963>] dm_ctl_ioctl+0x13/0x20
[<ffffffff8116a4f8>] do_vfs_ioctl+0x98/0x560
[<ffffffff8116aa51>] sys_ioctl+0x91/0xa0
[<ffffffff81869f52>] system_call_fastpath+0x16/0x1b

Fix the space map checker code to return an appropriate ERR_PTR and have
dm_sm_disk_create() and dm_tm_create_internal() check for it with
IS_ERR.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/persistent-data/dm-space-map-checker.c | 24 ++++++++++----------
drivers/md/persistent-data/dm-space-map-disk.c | 11 ++++++++-
drivers/md/persistent-data/dm-transaction-manager.c | 8 +++++-
3 files changed, 28 insertions(+), 15 deletions(-)

--- a/drivers/md/persistent-data/dm-space-map-checker.c
+++ b/drivers/md/persistent-data/dm-space-map-checker.c
@@ -343,25 +343,25 @@ struct dm_space_map *dm_sm_checker_creat
int r;
struct sm_checker *smc;

- if (!sm)
- return NULL;
+ if (IS_ERR_OR_NULL(sm))
+ return ERR_PTR(-EINVAL);

smc = kmalloc(sizeof(*smc), GFP_KERNEL);
if (!smc)
- return NULL;
+ return ERR_PTR(-ENOMEM);

memcpy(&smc->sm, &ops_, sizeof(smc->sm));
r = ca_create(&smc->old_counts, sm);
if (r) {
kfree(smc);
- return NULL;
+ return ERR_PTR(r);
}

r = ca_create(&smc->counts, sm);
if (r) {
ca_destroy(&smc->old_counts);
kfree(smc);
- return NULL;
+ return ERR_PTR(r);
}

smc->real_sm = sm;
@@ -371,7 +371,7 @@ struct dm_space_map *dm_sm_checker_creat
ca_destroy(&smc->counts);
ca_destroy(&smc->old_counts);
kfree(smc);
- return NULL;
+ return ERR_PTR(r);
}

r = ca_commit(&smc->old_counts, &smc->counts);
@@ -379,7 +379,7 @@ struct dm_space_map *dm_sm_checker_creat
ca_destroy(&smc->counts);
ca_destroy(&smc->old_counts);
kfree(smc);
- return NULL;
+ return ERR_PTR(r);
}

return &smc->sm;
@@ -391,25 +391,25 @@ struct dm_space_map *dm_sm_checker_creat
int r;
struct sm_checker *smc;

- if (!sm)
- return NULL;
+ if (IS_ERR_OR_NULL(sm))
+ return ERR_PTR(-EINVAL);

smc = kmalloc(sizeof(*smc), GFP_KERNEL);
if (!smc)
- return NULL;
+ return ERR_PTR(-ENOMEM);

memcpy(&smc->sm, &ops_, sizeof(smc->sm));
r = ca_create(&smc->old_counts, sm);
if (r) {
kfree(smc);
- return NULL;
+ return ERR_PTR(r);
}

r = ca_create(&smc->counts, sm);
if (r) {
ca_destroy(&smc->old_counts);
kfree(smc);
- return NULL;
+ return ERR_PTR(r);
}

smc->real_sm = sm;
--- a/drivers/md/persistent-data/dm-space-map-disk.c
+++ b/drivers/md/persistent-data/dm-space-map-disk.c
@@ -290,7 +290,16 @@ struct dm_space_map *dm_sm_disk_create(s
dm_block_t nr_blocks)
{
struct dm_space_map *sm = dm_sm_disk_create_real(tm, nr_blocks);
- return dm_sm_checker_create_fresh(sm);
+ struct dm_space_map *smc;
+
+ if (IS_ERR_OR_NULL(sm))
+ return sm;
+
+ smc = dm_sm_checker_create_fresh(sm);
+ if (IS_ERR(smc))
+ dm_sm_destroy(sm);
+
+ return smc;
}
EXPORT_SYMBOL_GPL(dm_sm_disk_create);

--- a/drivers/md/persistent-data/dm-transaction-manager.c
+++ b/drivers/md/persistent-data/dm-transaction-manager.c
@@ -345,8 +345,10 @@ static int dm_tm_create_internal(struct
}

*sm = dm_sm_checker_create(inner);
- if (!*sm)
+ if (IS_ERR(*sm)) {
+ r = PTR_ERR(*sm);
goto bad2;
+ }

} else {
r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location,
@@ -365,8 +367,10 @@ static int dm_tm_create_internal(struct
}

*sm = dm_sm_checker_create(inner);
- if (!*sm)
+ if (IS_ERR(*sm)) {
+ r = PTR_ERR(*sm);
goto bad2;
+ }
}

return 0;