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| if tracing::enabled!(Level::DEBUG) { | ||
| nc.enable_actor_debugging(); | ||
| } |
maksmore
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Jun 18, 2025
This took me forever to diagnose. After testing many different configurations (diff fendermint configs, diff commit refs, old localnet vs. new localnet, node restart sequences), I saw that changing the fendermint log level on a live network lead to a consensus failure... which is, super weird and didn't make any sense. I finally realized this is related to actor debugging. The actor debug flag cannot change on a live network due to how debugging works with the FVM / Wasmtime. Since WASM modules can't actually log to stdout/err, they are returned via syscall, which effects the respond data for a function call. The upshot is that changing to/from actor debugging on a live network leads to non-determinism and consensus failures. This can now happen when the fendermint log level goes from `info` to `debug` or `debug` to `info`, due to this change which ties the actor debugging flag to the fendermint log level introduced in #610. I hysterically commented "perfect" on this change :) Initial consensus failure: ``` E[2025-06-13|05:39:34.296] CONSENSUS FAILURE!!! module=consensus err="+2/3 committed an invalid block: wrong Block.Header.LastResultsHash. Expected 165B026A01F89BE3D648285701BA0A5E679050E0C1ADE78B4F0D124897F56CB4, got D6372018325A08E8AF1D65C8C63283783DADC5EA5E90B8C141F4B10868729B32" stack="goroutine 2626 [running]:\nruntime/debug.Stack()\n\truntime/debug/stack.go:24 +0x5e\ngithub.com/cometbft/cometbft/consensus.(*State).receiveRoutine.func2()\n\tgithub.com/cometbft/cometbft/consensus/state.go:737 +0x46\npanic({0xf78a00?, 0xc001b0cca0?})\n\truntime/panic.go:770 +0x132\ngithub.com/cometbft/cometbft/consensus.(*State).finalizeCommit(0xc000325888, 0x333)\n\tgithub.com/cometbft/cometbft/consensus/state.go:1651 +0xfb3\ngithub.com/cometbft/cometbft/consensus.(*State).tryFinalizeCommit(0xc000325888, 0x333)\n\tgithub.com/cometbft/cometbft/consensus/state.go:1620 +0x2e8\ngithub.com/cometbft/cometbft/consensus.(*State).handleCompleteProposal(0xc000325888, 0x333)\n\tgithub.com/cometbft/cometbft/consensus/state.go:2016 +0x372\ngithub.com/cometbft/cometbft/consensus.(*State).handleMsg(0xc000325888, {{0x131e3e0, 0xc0027a4ff0}, {0xc00035a810, 0x28}})\n\tgithub.com/cometbft/cometbft/consensus/state.go:847 +0x178\ngithub.com/cometbft/cometbft/consensus.(*State).receiveRoutine(0xc000325888, 0x0)\n\tgithub.com/cometbft/cometbft/consensus/state.go:773 +0x3f1\ncreated by github.com/cometbft/cometbft/consensus.(*State).OnStart in goroutine 2568\n\tgithub.com/cometbft/cometbft/consensus/state.go:384 +0x10c\n" ``` Later you will see: ``` E[2025-06-13|15:39:23.489] Error in validation module=blockchain err="wrong Block.Header.LastResultsHash. Expected CBE836990A8F3B39C27F40D7A7D39240064170C99BA8E7315B6A9E802AD10B3E, got F56F3216717F0641D8B8720918A4B425448E2B3F25BE20F43D2E544DF526DAE7" ``` Ideally, we could somehow alter this flag without rebuilding fendermint, but we need to think about how to do that in a way that's non "configuration". Signed-off-by: Sander Pick <sanderpick@gmail.com>
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Log observability tracing events with log level
DEBUGto have theINFOlog stream clean.Close #605