On 6/25/20 9:25 AM, Vladimir Sementsov-Ogievskiy wrote:
client_close doesn't guarantee that client is closed: nbd_trip() keeps
reference to it. Let's wait for nbd_trip to finish.
Without this fix, the following crash is possible:
- export bitmap through unternal Qemu NBD server
internal
- connect a client
- shutdown Qemu
On shutdown nbd_export_close_all is called, but it actually don't wait
for nbd_trip() to finish and to release its references. So, export is
not release, and exported bitmap remains busy, and on try to remove the
bitmap (which is part of bdrv_close()) the assertion fairs:
fails
bdrv_release_dirty_bitmap_locked: Assertion `!bdrv_dirty_bitmap_busy(bitmap)'
failed
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
nbd/server.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/nbd/server.c b/nbd/server.c
index 20754e9ebc..5e27a8d31a 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1419,6 +1419,8 @@ static void client_close(NBDClient *client, bool
negotiated)
qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH,
NULL);
+ AIO_WAIT_WHILE(client->exp->ctx, client->recv_coroutine);
+
/* Also tell the client, so that they release their reference. */
if (client->close_fn) {
client->close_fn(client, negotiated);
@@ -2450,6 +2452,7 @@ static coroutine_fn void nbd_trip(void *opaque)
trace_nbd_trip();
if (client->closing) {
+ client->recv_coroutine = NULL;
nbd_client_put(client);
return;
}
Reviewed-by: Eric Blake <ebl...@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
