What is a buffer deadlock?
A buffer deadlock is said to occur when a process holding buffer resources cannot proceed until it obtains additional buffer resources, but the buffer resources required are currently in use by some other process, and this process cannot proceed until they obtain resources held by the first process.
See also: viscious cycle, dark circle, bad news.
Design to prevent them. Using tools such as conservative allocation algorithms such as the ones for use in sliding window protocols like HDLC and DDCMP can be very useful.