The ring buffer mapping test failed after running the ftrace tests. This was due to some mismatched snapshot accounting that left the snapshot counter enabled when it was not, which prevents the ring buffer from being mapped.
Steven Rostedt (Google) (2): tracing: Fix snapshot counter going between two tracers that use it tracing: Decrement the snapshot if the snapshot trigger fails to register ---- kernel/trace/trace.c | 2 +- kernel/trace/trace_events_trigger.c | 5 ++++- 2 files changed, 5 insertions(+), 2 deletions(-)