From 35e26e94d8a13ef3f24a66374aff815e370f8843 Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Fri, 24 Jan 2014 10:02:27 -0800 Subject: [PATCH] Fix a spuriously tripped assert in select() The race here happened when a port had its deschedule in select() canceled, but the other chan had already been dropped. This meant that the DISCONNECTED case was hit in abort_selection, but the to_wake cell hadn't been emptied yet (this was done after aborting), causing an assert in abort_selection to trip. To fix this, the to_wake cell is just emptied before abort_selection is called (we know that we're the owner of it already). --- src/libstd/comm/select.rs | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/libstd/comm/select.rs b/src/libstd/comm/select.rs index 6a10ac56a4ef4..5aa8687a5bb7f 100644 --- a/src/libstd/comm/select.rs +++ b/src/libstd/comm/select.rs @@ -199,11 +199,14 @@ impl Select { if (*packet).decrement() { Ok(()) } else { + // Empty to_wake first to avoid tripping an assertion in + // abort_selection in the disconnected case. + let task = (*packet).to_wake.take_unwrap(); (*packet).abort_selection(false); (*packet).selecting.store(false, SeqCst); ready_index = i; ready_id = (*packet).selection_id; - Err((*packet).to_wake.take_unwrap()) + Err(task) } });