A vulnerability in the Linux kernel's ring-buffer implementation was fixed to correct an off-by-one error in the sub-buffer array base calculation within rb_meta_subbuf_idx(). This flaw caused an incorrect index to be returned, leading to a NULL dereference when userspace maps trace_pipe_raw, which could result in trace data loss from the previous boot. The issue was due to misalignment in calculating the sub-buffer array base, which has now been corrected by inverting the calculation using rb_subbufs_from_meta().