alt Hacker NewsAs someone who works with hardware, hard to repo bugs can take months to track down. Your code, the compiler, or the hardware itself (which is often a complex ball of IP from dozens of manufacturers held together with a NoC) could all be a problem. The extra fun bugs are when a bug is due to problems in two or three of them combining together in the perfect storm to make a mega bug that is impossible to reproduce in isolation.
Random example: I once worked on a debug where you were not allowed to send zero length packets due to a known HW bug. Okay fine, work around in SW. Turns out there was an HW eviction timer that was disabled. It was connected to a counter that counted sys clk ticks. Turns out it was not disabled entirely properly due to SW bug, so once every 2^32 ticks, it would trigger an evection, and if the queue happened to be empty, it would send a ZLP, which triggered the first bug (hard hang the system in a way that breaks the debugger). There were dozens of ways that could hard hang the system, this was just one. Good luck debugging that in two days.