peer_control: fix leak false positive.

We generally hang things off our JSON response (this pattern predates
tmpctx!) but sometimes it gets reported as a memleak.  I'd prefer not
to mark JSON responses as "notleak", since they can be allocated for
a while), so use tmpctx here.

```
E           ValueError:
E           Node errors:
E           Global errors:
E            - Node /tmp/ltests-spnausnb/test_htlc_out_timeout_1/lightning-1/ has memory leaks: [
E               {
E                   "backtrace": [
E                       "ccan/ccan/tal/tal.c:442 (tal_alloc_)",
E                       "ccan/ccan/tal/tal.c:471 (tal_alloc_arr_)",
E                       "wallet/wallet.c:1775 (wallet_state_change_get)",
E                       "lightningd/peer_control.c:922 (json_add_channel)",
E                       "lightningd/peer_control.c:1424 (json_add_peer)",
E                       "lightningd/peer_control.c:1454 (json_listpeers)",
E                       "lightningd/jsonrpc.c:643 (command_exec)",
E                       "lightningd/jsonrpc.c:767 (rpc_command_hook_final)",
E                       "lightningd/plugin_hook.c:275 (plugin_hook_call_)",
E                       "lightningd/jsonrpc.c:855 (plugin_hook_call_rpc_command)",
E                       "lightningd/jsonrpc.c:942 (parse_request)",
E                       "lightningd/jsonrpc.c:1033 (read_json)",
E                       "ccan/ccan/io/io.c:59 (next_plan)",
E                       "ccan/ccan/io/io.c:435 (io_do_always)",
E                       "ccan/ccan/io/poll.c:300 (handle_always)",
E                       "ccan/ccan/io/poll.c:377 (io_loop)",
E                       "lightningd/io_loop_with_timers.c:24 (io_loop_with_timers)",
E                       "lightningd/lightningd.c:1097 (main)"
E                   ],
E                   "label": "wallet/wallet.c:1775:struct state_change_entry[]",
E                   "parents": [
E                       "common/json_stream.c:29:struct json_stream",
E                       "ccan/ccan/io/io.c:91:struct io_conn",
E                       "lightningd/lightningd.c:116:struct lightningd"
E                   ],
E                   "value": "0x55c6b02150b8"
E               }
E           ]
```

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2021-04-08 10:31:35 +09:30 committed by Christian Decker
parent 8cef2c17ad
commit ade10e7fc4

View File

@ -919,7 +919,7 @@ static void json_add_channel(struct lightningd *ld,
json_add_num(response, "max_accepted_htlcs",
channel->our_config.max_accepted_htlcs);
state_changes = wallet_state_change_get(ld->wallet, response, channel->dbid);
state_changes = wallet_state_change_get(ld->wallet, tmpctx, channel->dbid);
json_array_start(response, "state_changes");
for (size_t i = 0; i < tal_count(state_changes); i++) {
json_object_start(response, NULL);