diff options
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index e178fe19973e..1334c411c722 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -735,7 +735,16 @@ static struct table_device *open_table_device(struct mapped_device *md, return ERR_PTR(-ENOMEM); refcount_set(&td->count, 1); - bdev_file = bdev_file_open_by_dev(dev, mode, _dm_claim_ptr, NULL); + /* + * Open the backing device with kernel rather than caller + * credentials. Otherwise the caller's credentials would be + * pinned in bdev_file->f_cred until the table device is closed. + * That would keep the caller's thread keyring alive long beyond the + * lifetime of the caller, breaking userspace expectation (e.g. + * cryptsetup(8) leaking the LUKS volume key). + */ + scoped_with_kernel_creds() + bdev_file = bdev_file_open_by_dev(dev, mode, _dm_claim_ptr, NULL); if (IS_ERR(bdev_file)) { r = PTR_ERR(bdev_file); goto out_free_td; @@ -2098,8 +2107,17 @@ static bool dm_poll_dm_io(struct dm_io *io, struct io_comp_batch *iob, WARN_ON_ONCE(!dm_tio_is_normal(&io->tio)); /* don't poll if the mapped io is done */ - if (atomic_read(&io->io_count) > 1) - bio_poll(&io->tio.clone, iob, flags); + if (atomic_read(&io->io_count) > 1) { + /* + * DM hides the target queues from the upper poller, which may + * decide it is safe to spin on a single stacked queue. Do not + * pass that spinning policy down to a target queue: one slow + * clone could keep the task inside dm_poll_bio() for a long + * time. Poll target bios once and let the caller decide + * whether to keep polling, reap completions or reschedule. + */ + bio_poll(&io->tio.clone, iob, flags | BLK_POLL_ONESHOT); + } /* bio_poll holds the last reference */ return atomic_read(&io->io_count) == 1; |