Intermittent Time Decrement Issue in Geth 1.12 Smart Contract Calls

[AntonGulak]

We’re observing a rare and intermittent issue in Geth 1.12 where consecutive calls to two functions—setTime() (which sets time = now) followed by getTime() (which returns the stored time)—occasionally result in inconsistent values. Specifically, after setting time and subsequently retrieving it, the second getTime() call sometimes returns a value exactly one unit lower than the previous call. For example, the first retrieval might return 0xaab, while the next consecutive retrieval returns 0xaaa (exactly -1), despite blocks being mined at 5-second intervals and the calls being strictly sequential. This anomaly has occurred only a few times over several years of continuous node operation, and the root cause remains unknown.

Has anyone experienced a similar issue or can shed light on why this might be happening?

[MariusVanDerWijden]

Interesting, do you have some code for us to try to repro it better? On what kind of network are you running? Maybe in the case of a reorg where the miner mines a block a second earlier or with a bit of clock skew this might happen.

Sorry for replying so late to this, but it would be really interesting to understand your setup!

[holiman]

I sincerely don't understand this report. setTime() -- on what? Are we talking about a contract with a method so named? Please be specific, provide solidity-code of any contracts you refer to, and also how the contract is invoked when you detect the error.