diff options
| -rw-r--r-- | library/std/src/sync/mpmc/list.rs | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/library/std/src/sync/mpmc/list.rs b/library/std/src/sync/mpmc/list.rs index ec6c0726ac7..406a331a309 100644 --- a/library/std/src/sync/mpmc/list.rs +++ b/library/std/src/sync/mpmc/list.rs @@ -549,6 +549,18 @@ impl<T> Channel<T> { let mut head = self.head.index.load(Ordering::Acquire); let mut block = self.head.block.load(Ordering::Acquire); + // If we're going to be dropping messages we need to synchronize with initialization + if head >> SHIFT != tail >> SHIFT { + // The block can be null here only if a sender is in the process of initializing the + // channel while another sender managed to send a message by inserting it into the + // semi-initialized channel and advanced the tail. + // In that case, just wait until it gets initialized. + while block.is_null() { + backoff.spin_heavy(); + block = self.head.block.load(Ordering::Acquire); + } + } + unsafe { // Drop all messages between head and tail and deallocate the heap-allocated blocks. while head >> SHIFT != tail >> SHIFT { |