4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mikulas Patocka <mpatocka@xxxxxxxxxx> commit bc86a41e96c5b6f07453c405e036d95acc673389 upstream. If the dm-integrity superblock was corrupted in such a way that the journal_sections field was zero, the integrity target would deadlock because it would wait forever for free space in the journal. Detect this situation and refuse to activate the device. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Fixes: 7eada909bfd7 ("dm: add integrity target") Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm-integrity.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -3021,6 +3021,11 @@ static int dm_integrity_ctr(struct dm_ta ti->error = "Block size doesn't match the information in superblock"; goto bad; } + if (!le32_to_cpu(ic->sb->journal_sections)) { + r = -EINVAL; + ti->error = "Corrupted superblock, journal_sections is 0"; + goto bad; + } /* make sure that ti->max_io_len doesn't overflow */ if (ic->sb->log2_interleave_sectors < MIN_LOG2_INTERLEAVE_SECTORS || ic->sb->log2_interleave_sectors > MAX_LOG2_INTERLEAVE_SECTORS) {