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authorLars Ellenberg <lars.ellenberg@linbit.com>2017-08-29 11:20:44 +0300
committerJens Axboe <axboe@kernel.dk>2017-08-30 00:34:46 +0300
commitcde81d99afa4112eecef3f45129b5827f6ac158e (patch)
tree07f4b2a5f05448cda6791ed5ec146ca55e987c09 /drivers/block
parent33d32fa7120ed184efc9be1ea3c016109b4fea84 (diff)
downloadlinux-cde81d99afa4112eecef3f45129b5827f6ac158e.tar.xz
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>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/drbd/drbd_receiver.c3
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);