fuzz: Create a block template in tx_pool targets #21798

pull MarcoFalke wants to merge 4 commits into bitcoin:master from MarcoFalke:2104-fuzzMempool changing 4 files +80 −31

MarcoFalke commented at 6:55 PM on April 28, 2021: member

Relatively simple check to ensure a block can always be created from the mempool
fuzz: Allow to pass min/max to ConsumeTime fae2c8bc54

fuzz: Use correct variant of ConsumeRandomLengthString instead of hardcoding a maximum size

This is technically a breaking change.

This allows the fuzz engine to pick the right size,
also larger sizes, if needed.

fab646b8ea

fuzz: Limit mocktime to MTP in tx_pool targets

This is needed for the next commit to generate blocks.

Also, apply the same mocking strategies to both targets.

fa61ce5cf5

DrahtBot added the label Tests on Apr 28, 2021
practicalswift commented at 6:11 AM on April 29, 2021: contributor

Concept ACK

Touches only src/test/fuzz/

MarcoFalke commented at 12:03 PM on April 29, 2021: member

Looks like ci fails due to:

policy/feerate.cpp:26:34: runtime error: signed integer overflow: 1887171891083620 * 5555 cannot be represented in type 'long'
    [#0](/bitcoin-bitcoin/0/) 0x560eb0295c97 in CFeeRate::GetFee(unsigned long) const policy/feerate.cpp:26:34
    [#1](/bitcoin-bitcoin/1/) 0x560eafb6409b in BlockAssembler::addPackageTxs(int&, int&) miner.cpp:378:43
    [#2](/bitcoin-bitcoin/2/) 0x560eafb60c86 in BlockAssembler::CreateNewBlock(CScript const&) miner.cpp:150:5
    [#3](/bitcoin-bitcoin/3/) 0x560eafa21cae in (anonymous namespace)::Finish(FuzzedDataProvider&, (anonymous namespace)::MockedTxPool&, CChainState&) test/fuzz/tx_pool.cpp:89:41
    [#4](/bitcoin-bitcoin/4/) 0x560eafa1e237 in (anonymous namespace)::tx_pool_standard_fuzz_target(Span<unsigned char const>) test/fuzz/tx_pool.cpp:272:5
    
...

SUMMARY: UndefinedBehaviorSanitizer: signed-integer-overflow policy/feerate.cpp:26:34 in

MarcoFalke commented at 5:50 AM on April 30, 2021: member

(ci now green)
adamjonas commented at 5:53 PM on May 5, 2021: member

Tested fa03232 with DEBUG=1 and observed some nice coverage increases.

My setup is still showing the CI's UB error both in faf3e9d and fa03232, but that just might be due to my own lack of understanding or a compile issue on my part.
fuzz: Create a block template in tx_pool targets fa03d0acd6
MarcoFalke force-pushed on May 5, 2021
MarcoFalke commented at 6:12 PM on May 5, 2021: member

squashed the commits. bisecting should now work again.
practicalswift commented at 9:39 PM on May 5, 2021: contributor

Tested ACK fa03d0acd6bd8bb6d3d5227512f042ff537ad993

As expected the coverage achieved by the tx_pool fuzzing harness is dramatically improved with this patch applied.

Nice work!
MarcoFalke merged this on May 6, 2021
MarcoFalke closed this on May 6, 2021
MarcoFalke deleted the branch on May 6, 2021
sidhujag referenced this in commit 3101af3087 on May 6, 2021
gwillen referenced this in commit b2376cfef6 on Jun 1, 2022
DrahtBot locked this on Aug 16, 2022

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