miner: exit loop when downloader Done or Failed#200
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Following the logic of the comment at the method, this fixes a regression introduced at 7cf56d6 , which would allow external parties to DoS with blocks, preventing mining progress. Signed-off-by: meows <b5c6@protonmail.com>
Signed-off-by: meows <b5c6@protonmail.com>
Signed-off-by: meows <b5c6@protonmail.com>
Contributor
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after implementing these changes force interupt, (e.g ctrl+c) is not exiting cleanly, as it did prior to these changes. I am forced to interupt until panic, otherwise looping on looking for peers. |
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Author
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@iquidus Yes, it needs more work. The channels are not getting closed. See upstream PR for comments as well. |
This helper function would return an affirmation on the first positive match on a desired bool. This was imprecise; it return false positives by not waiting initially for an 'updated' value. This fix causes TestMiner_2 to fail, which is expected. Signed-off-by: meows <b5c6@protonmail.com>
This test demonstrated the imprecision of the test helper function waitForMiningState. This function has been fixed with 6d365c2851, and this test test may now be removed. Signed-off-by: meows <b5c6@protonmail.com>
See comment for logic. Signed-off-by: meows <b5c6@protonmail.com>
We expect that once the downloader emits a DoneEvent, signaling a successful sync, that subsequent StartEvents are not longer permitted to stop the miner. This prevents a security vulnerability where forced syncs via fake high blocks would stall mining operation. Signed-off-by: meows <b5c6@protonmail.com>
- Break downloader event handling into event separating Done and Failed events. We need to treat these cases differently since a DoneEvent should prevent the miner from being stopped on subsequent downloader Start events. - Use canStop state to handle the one-off case when a downloader first succeeds. Signed-off-by: meows <b5c6@protonmail.com>
Signed-off-by: meows <b5c6@protonmail.com>
Signed-off-by: meows <b5c6@protonmail.com>
This makes mining pause/start logic regarding downloader events more explicit. Instead of eternally handling downloader events after the first done event, the subscription is closed when downloader events are no longer actionable. Signed-off-by: meows <b5c6@protonmail.com>
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@iquidus @ziogaschr PTAL |
ziogaschr
reviewed
Oct 5, 2020
Signed-off-by: meows <b5c6@protonmail.com>
Signed-off-by: meows <b5c6@protonmail.com>
The go routine handling the downloader events handling vars in parallel with the parent routine, causing a race condition. This change, though ugly, remove the condition while still allowing the downloader event subscription to be closed when the miner has no further use for it (ie DoneEvent).
ziogaschr
approved these changes
Oct 8, 2020
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Following the logic of the comment at the method,
this fixes a regression introduced at 7cf56d6
, which would allow external parties to DoS with
blocks, preventing mining progress.
Rel #199
Corresponding upstream PR at ethereum/go-ethereum#21653