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| author | Hou Tao <houtao1@huawei.com> | 2021-06-17 15:45:47 +0800 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2021-06-25 15:25:24 -0400 |
| commit | b6e58b5466b2959f83034bead2e2e1395cca8aeb (patch) | |
| tree | ebf6645e4a81fc7c3b79ac40c552de1c17e05e14 /drivers/md | |
| parent | 28436ba34b7d1b6af2a898d37ee678a1eb643db4 (diff) | |
| download | linux-b6e58b5466b2959f83034bead2e2e1395cca8aeb.tar.bz2 | |
dm btree remove: assign new_root only when removal succeeds
remove_raw() in dm_btree_remove() may fail due to IO read error
(e.g. read the content of origin block fails during shadowing),
and the value of shadow_spine::root is uninitialized, but
the uninitialized value is still assign to new_root in the
end of dm_btree_remove().
For dm-thin, the value of pmd->details_root or pmd->root will become
an uninitialized value, so if trying to read details_info tree again
out-of-bound memory may occur as showed below:
general protection fault, probably for non-canonical address 0x3fdcb14c8d7520
CPU: 4 PID: 515 Comm: dmsetup Not tainted 5.13.0-rc6
Hardware name: QEMU Standard PC
RIP: 0010:metadata_ll_load_ie+0x14/0x30
Call Trace:
sm_metadata_count_is_more_than_one+0xb9/0xe0
dm_tm_shadow_block+0x52/0x1c0
shadow_step+0x59/0xf0
remove_raw+0xb2/0x170
dm_btree_remove+0xf4/0x1c0
dm_pool_delete_thin_device+0xc3/0x140
pool_message+0x218/0x2b0
target_message+0x251/0x290
ctl_ioctl+0x1c4/0x4d0
dm_ctl_ioctl+0xe/0x20
__x64_sys_ioctl+0x7b/0xb0
do_syscall_64+0x40/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixing it by only assign new_root when removal succeeds
Signed-off-by: Hou Tao <houtao1@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/persistent-data/dm-btree-remove.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/persistent-data/dm-btree-remove.c b/drivers/md/persistent-data/dm-btree-remove.c index b34af195bf2a..70532335c7c7 100644 --- a/drivers/md/persistent-data/dm-btree-remove.c +++ b/drivers/md/persistent-data/dm-btree-remove.c @@ -549,7 +549,8 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, delete_at(n, index); } - *new_root = shadow_root(&spine); + if (!r) + *new_root = shadow_root(&spine); exit_shadow_spine(&spine); return r; |