Systems and methods are disclosed for logging encoded diagnostic information from a sequence of processing operations, the processing operations generated by an activity in a computing environment. Diagnostic information is tracked by activity, across process boundaries where the processes can be in computationally isolated, or “sandboxed”. Within each process, diagnostic information for an activity is stored in an activity-specific buffer registered with a kernel in the computing environment. For each activity in the computing system, the kernel keeps a list of all processes that have performed, or are performing, a processing task of the activity. The kernel also keeps a reference to the activity-specific log buffers for the activity for each process associated with the activity. If a processing operation for an activity fails, all activity-specific logs from all processes that are associated with the activity can be collected. A report can be generated from the collected logs for the activity.