diff options
| author | Daniil Fedotov <dfedotov@pivotal.io> | 2017-11-22 17:27:48 +0000 |
|---|---|---|
| committer | Daniil Fedotov <dfedotov@pivotal.io> | 2017-11-23 12:03:02 +0000 |
| commit | 5977c1a0ba6bded40b4a20a5317c4f62489743cf (patch) | |
| tree | 1a3ba80f928e5b473b2ade8938e519d48f445730 /src | |
| parent | d704c5501b423244bf63e458f1192518915150bb (diff) | |
| download | rabbitmq-server-git-5977c1a0ba6bded40b4a20a5317c4f62489743cf.tar.gz | |
Avoid infinite loop when dropping gm queue entries.
Since `out` operation on empty queue is idempotent `queue:out(B) = {empty, B}`,
there can be a potential infinite loop when dropping messages.
Matching that there is a value to drop.
Empty A queue should be handled by second clause.
Related to #779
Diffstat (limited to 'src')
| -rw-r--r-- | src/gm.erl | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/gm.erl b/src/gm.erl index cf3e217010..d6005fe554 100644 --- a/src/gm.erl +++ b/src/gm.erl @@ -1354,9 +1354,12 @@ find_common(A, B, Common) -> find_common(A1, B1, queue:in(Val, Common)); {{empty, _A}, _} -> {Common, B}; - {_, {_, B1}} -> + %% Drop value from B. + %% Match value to avoid infinite loop, since {empty, B} = queue:out(B). + {_, {{value, _}, B1}} -> find_common(A, B1, Common); - {{_, A1}, _} -> + %% Drop value from A. Empty A should be matched by second close. + {{{value, _}, A1}, _} -> find_common(A1, B, Common) end. |