diff options
| author | Caleb Sander Mateos <csander@purestorage.com> | 2025-12-12 17:19:49 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-12-20 12:56:37 -0700 |
| commit | daa24603d9f0808929514ee62ced30052ca7221c (patch) | |
| tree | 47614545397cf779b5768e09462a6ddbd7b765de | |
| parent | af65faf34f6e9919bdd2912770d25d2a73cbcc7c (diff) | |
ublk: clean up user copy references on ublk server exit
If a ublk server process releases a ublk char device file, any requests
dispatched to the ublk server but not yet completed will retain a ref
value of UBLK_REFCOUNT_INIT. Before commit e63d2228ef83 ("ublk: simplify
aborting ublk request"), __ublk_fail_req() would decrement the reference
count before completing the failed request. However, that commit
optimized __ublk_fail_req() to call __ublk_complete_rq() directly
without decrementing the request reference count.
The leaked reference count incorrectly allows user copy and zero copy
operations on the completed ublk request. It also triggers the
WARN_ON_ONCE(refcount_read(&io->ref)) warnings in ublk_queue_reinit()
and ublk_deinit_queue().
Commit c5c5eb24ed61 ("ublk: avoid ublk_io_release() called after ublk
char dev is closed") already fixed the issue for ublk devices using
UBLK_F_SUPPORT_ZERO_COPY or UBLK_F_AUTO_BUF_REG. However, the reference
count leak also affects UBLK_F_USER_COPY, the other reference-counted
data copy mode. Fix the condition in ublk_check_and_reset_active_ref()
to include all reference-counted data copy modes. This ensures that any
ublk requests still owned by the ublk server when it exits have their
reference counts reset to 0.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: e63d2228ef83 ("ublk: simplify aborting ublk request")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/ublk_drv.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index cfd2132410dd..49c208457198 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1607,8 +1607,7 @@ static bool ublk_check_and_reset_active_ref(struct ublk_device *ub) { int i, j; - if (!(ub->dev_info.flags & (UBLK_F_SUPPORT_ZERO_COPY | - UBLK_F_AUTO_BUF_REG))) + if (!ublk_dev_need_req_ref(ub)) return false; for (i = 0; i < ub->dev_info.nr_hw_queues; i++) { |