Kernel bugs can remain undetected for years, with an average lifespan of 2.1 years based on an analysis of 125,183 bugs in the Linux kernel's history. Some bugs linger much longer; for instance, a buffer overflow in ethtool was hidden for over 20 years. The study highlights that certain subsystems, like CAN bus drivers and SCTP networking, have even worse records, averaging 4.2 and 4.0 years respectively. Surprisingly, about 20% of bugs can hide for more than five years. The author developed a tool that identifies 92% of historical bugs at commit time, showcasing substantial progress in bug detection. The analysis began with a smaller dataset from 2025, which showed that nearly half of the bugs were found within a year. Upon mining the full history since 2005, the researcher discovered that the percentage of bugs found within a year improved significantly to 57%. Bugs introduced in recent years are being fixed faster, with 69% of those from 2022 discovered within a year, compared to none from 2010. However, this data is somewhat skewed since newer bugs can't have long lifetimes yet. The real comparison shows ongoing improvement in speed of detection, driven by better tools and more contributors. Different types of bugs have varying lifetimes, with race conditions being the hardest to identify, averaging 5.1 years. Memory-related bugs like use-after-free and integer-overflow take around 3.2 and 3.9 years, respectively. The analysis also reveals that 30% of bugs are self-fixes, where the fix is applied in the same commit that introduces the bug, complicating the picture further. Overall, while kernel bug detection has improved, a significant backlog of older bugs remains, particularly in niche subsystems with less testing coverage.