diff options
| author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2017-08-29 10:20:44 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-08-29 23:34:46 +0200 |
| commit | cde81d99afa4112eecef3f45129b5827f6ac158e (patch) | |
| tree | 07f4b2a5f05448cda6791ed5ec146ca55e987c09 | |
| parent | drbd: fix potential deadlock when trying to detach during handshake (diff) | |
| download | linux-cde81d99afa4112eecef3f45129b5827f6ac158e.tar.xz linux-cde81d99afa4112eecef3f45129b5827f6ac158e.zip | |
drbd: fix race between handshake and admin disconnect/down
conn_try_disconnect() could potentialy hit the BUG_ON()
in _conn_set_state() where it iterates over _drbd_set_state()
and "asserts" via BUG_ON() that the latter was successful.
If the STATE_SENT bit was not yet visible to conn_is_valid_transition()
early in _conn_request_state(), but became visible before conn_set_state()
later in that call path, we could hit the BUG_ON() after _drbd_set_state(),
because it returned SS_IN_TRANSIENT_STATE.
To avoid that race, we better protect set_bit(SENT_STATE) with the spinlock.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/drbd/drbd_receiver.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 248966727bf6..5e090a1e4f91 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -1100,7 +1100,10 @@ randomize: idr_for_each_entry(&connection->peer_devices, peer_device, vnr) mutex_lock(peer_device->device->state_mutex); + /* avoid a race with conn_request_state( C_DISCONNECTING ) */ + spin_lock_irq(&connection->resource->req_lock); set_bit(STATE_SENT, &connection->flags); + spin_unlock_irq(&connection->resource->req_lock); idr_for_each_entry(&connection->peer_devices, peer_device, vnr) mutex_unlock(peer_device->device->state_mutex); |