Comments on: Alert: dumpblock flaw in bitcoind can cause gbw-node to incorrectly report transactions http://jfxpt.com/2021/alert-dumpblock-flaw-in-bitcoind-can-cause-gbw-node-to-incorrectly-report-transactions/ The search for invariants Thu, 16 Apr 2026 14:46:54 +0000 http://polimedia.us hourly 1 By: Smartening up gbw-node « Fixpoint http://jfxpt.com/2021/alert-dumpblock-flaw-in-bitcoind-can-cause-gbw-node-to-incorrectly-report-transactions/#comment-2356 Smartening up gbw-node « Fixpoint Wed, 05 Apr 2023 01:38:31 +0000 http://fixpoint.welshcomputing.com/?p=149#comment-2356 [...] A flurry of coding and testing ensued, and by the time it was done I had a stack of five patches, bringing: multiple usability improvements, improved portability to older Python interpreters, a minor reduction in scan time per byte, a dramatic reduction in scan time overhead per block, and finally a path toward full removal of the sorest point, the notorious dumpblock horror. [...] [...] A flurry of coding and testing ensued, and by the time it was done I had a stack of five patches, bringing: multiple usability improvements, improved portability to older Python interpreters, a minor reduction in scan time per byte, a dramatic reduction in scan time overhead per block, and finally a path toward full removal of the sorest point, the notorious dumpblock horror. [...]

]]> By: Mapping the bitcoind block acceptance code, with bonus patch for index access « Fixpoint http://jfxpt.com/2021/alert-dumpblock-flaw-in-bitcoind-can-cause-gbw-node-to-incorrectly-report-transactions/#comment-2010 Mapping the bitcoind block acceptance code, with bonus patch for index access « Fixpoint Tue, 22 Mar 2022 04:12:06 +0000 http://fixpoint.welshcomputing.com/?p=149#comment-2010 [...] be valid. One would imagine that these can't show up on the active chain, but at the very least my orphans and losers classification was incomplete, and the "dumpblock" flaw worse than previously rea...: there's a third category of, shall we say, hopeful blocks, with validity unknown as they've never [...] [...] be valid. One would imagine that these can't show up on the active chain, but at the very least my orphans and losers classification was incomplete, and the "dumpblock" flaw worse than previously rea...: there's a third category of, shall we say, hopeful blocks, with validity unknown as they've never [...]

]]> By: Gales Bitcoin Wallet (re)release « Fixpoint http://jfxpt.com/2021/alert-dumpblock-flaw-in-bitcoind-can-cause-gbw-node-to-incorrectly-report-transactions/#comment-1610 Gales Bitcoin Wallet (re)release « Fixpoint Fri, 03 Dec 2021 08:54:21 +0000 http://fixpoint.welshcomputing.com/?p=149#comment-1610 [...] Investigation and fix for a bug discovered in earlier Bitcoin Foundation work on the underlying bitc... [...] [...] Investigation and fix for a bug discovered in earlier Bitcoin Foundation work on the underlying bitc... [...]

]]> By: Jacob Welsh http://jfxpt.com/2021/alert-dumpblock-flaw-in-bitcoind-can-cause-gbw-node-to-incorrectly-report-transactions/#comment-672 Jacob Welsh Mon, 28 Jun 2021 16:48:47 +0000 http://fixpoint.welshcomputing.com/?p=149#comment-672 > I am guilty of using the incorrect terminology, referring to loser blocks as orphan blocks. As far as I know we were all living in sin. > afaik, nodes do not feed known loser blocks to other nodes. Unless they're looking to make trouble. > I am guilty of using the incorrect terminology, referring to loser blocks as orphan blocks.

As far as I know we were all living in sin.

> afaik, nodes do not feed known loser blocks to other nodes.

Unless they're looking to make trouble.

]]> By: whaack http://jfxpt.com/2021/alert-dumpblock-flaw-in-bitcoind-can-cause-gbw-node-to-incorrectly-report-transactions/#comment-668 whaack Sun, 27 Jun 2021 16:56:26 +0000 http://fixpoint.welshcomputing.com/?p=149#comment-668 Thanks for the clarification regarding orphan blocks vs loser blocks. I am guilty of using the incorrect terminology, referring to loser blocks as orphan blocks. Receiving a loser block via the pre-patch'd dumpblock is much greater once your node is sync'd. This is because, afaik, nodes do not feed known loser blocks to other nodes. So as your syncing the earlier blocks, fully sync'd nodes are only going to send you winner blocks. Then, once you are at the tip with all your peers, those peers can no longer filter out soon-to-be-loser blocks, seeing as it can only be known that the blocks will be losers in the future. I sync'd my node recently, and thus discovered my first problematic block at height 685,135. Since you and dorion and others sync'd your trb much earlier than mine, I'd imagine that you loaded a couple of loser blocks with heights between, say, ~500,000 and 685,135. Thanks for the clarification regarding orphan blocks vs loser blocks. I am guilty of using the incorrect terminology, referring to loser blocks as orphan blocks.

Receiving a loser block via the pre-patch'd dumpblock is much greater once your node is sync'd. This is because, afaik, nodes do not feed known loser blocks to other nodes. So as your syncing the earlier blocks, fully sync'd nodes are only going to send you winner blocks. Then, once you are at the tip with all your peers, those peers can no longer filter out soon-to-be-loser blocks, seeing as it can only be known that the blocks will be losers in the future.

I sync'd my node recently, and thus discovered my first problematic block at height 685,135. Since you and dorion and others sync'd your trb much earlier than mine, I'd imagine that you loaded a couple of loser blocks with heights between, say, ~500,000 and 685,135.

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