Re: [Libguestfs] [PATCH v4 23/24] nbd/server: Prepare for per-request filtering of BLOCK_STATUS

On Thu, Jun 08, 2023 at 08:56:52AM -0500, Eric Blake wrote: > The next commit will add support for the optional extension > NBD_CMD_FLAG_PAYLOAD during NBD_CMD_BLOCK_STATUS, where the client can > request that the server only return a subset of negotiated contexts, > rather than all contexts. To make that task easier, this patch > populates the list of contexts to return on a per-command basis (for > now, identical to the full set of negotiated contexts). > > Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; > --- > > +++ b/nbd/server.c > @@ -2491,6 +2491,8 @@ static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, NBDRequest * > error_setg(errp, "No memory"); > return -ENOMEM; > } > + } else if (request->type == NBD_CMD_BLOCK_STATUS) { > + request->contexts = &client->contexts; > } THere are paths where request->contexts is left NULL but request->type was set... > @@ -2841,6 +2848,11 @@ static coroutine_fn void nbd_trip(void *opaque) > } else { > ret = nbd_handle_request(client, &request, req->data, &local_err); > } > + if (request.type == NBD_CMD_BLOCK_STATUS && > + request.contexts != &client->contexts) { > + g_free(request.contexts->bitmaps); > + g_free(request.contexts); > + } so I think this also needs to be tweaked to check that request.contexts is non-NULL before dereferencing to free bitmaps.