From: Mike Snitzer 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:[] [] dm_bufio_get_block_size+0x9/0x20 Call Trace: [] dm_bm_block_size+0xe/0x10 [] sm_ll_init+0x78/0xd0 [] sm_ll_new_disk+0x16/0xa0 [] dm_sm_disk_create+0xfe/0x160 [] dm_pool_metadata_open+0x16e/0x6a0 [] pool_ctr+0x3f0/0x900 [] dm_table_add_target+0x195/0x450 [] table_load+0xe4/0x330 [] ctl_ioctl+0x15a/0x2c0 [] dm_ctl_ioctl+0x13/0x20 [] do_vfs_ioctl+0x98/0x560 [] sys_ioctl+0x91/0xa0 [] 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 Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org Signed-off-by: Alasdair G Kergon --- 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(-) Index: linux-3.5-rc5/drivers/md/persistent-data/dm-space-map-checker.c =================================================================== --- linux-3.5-rc5.orig/drivers/md/persistent-data/dm-space-map-checker.c +++ linux-3.5-rc5/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; Index: linux-3.5-rc5/drivers/md/persistent-data/dm-space-map-disk.c =================================================================== --- linux-3.5-rc5.orig/drivers/md/persistent-data/dm-space-map-disk.c +++ linux-3.5-rc5/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); Index: linux-3.5-rc5/drivers/md/persistent-data/dm-transaction-manager.c =================================================================== --- linux-3.5-rc5.orig/drivers/md/persistent-data/dm-transaction-manager.c +++ linux-3.5-rc5/drivers/md/persistent-data/dm-transaction-manager.c @@ -347,8 +347,10 @@ 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, @@ -367,8 +369,10 @@ 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;