fuzz: reset connman state in p2p targets #35808

pull HowHsu wants to merge 1 commits into bitcoin:master from HowHsu:fuzz-connman changing 2 files +2 −0

HowHsu commented at 11:23 AM on July 26, 2026: contributor
Resets ConnmanTestMsg after StopNodes() in cmpctblock and p2p_handshake, matching the other reused-connman fuzz targets and preventing sticky CConnman state from leaking between corpus inputs.

Before this, deterministic-fuzz-coverage showed single inputs were stable, but all-input directory runs were not:
```
cmpctblock, src/net.cpp:4172
- Branch (4172:9): [True: 1.21k, False: 33.0k]
+ Branch (4172:9): [True: 613, False: 33.6k]
- Branch (4172:72): [True: 901, False: 311]
+ Branch (4172:72): [True: 497, False: 116]
```
```
p2p_handshake, src/net.cpp:4172
- Branch (4172:9): [True: 98, False: 1.67k]
+ Branch (4172:9): [True: 743, False: 1.03k]
- Branch (4172:72): [True: 90, False: 8]
+ Branch (4172:72): [True: 612, False: 131]
```
After the cmpctblock reset, deterministic-fuzz-coverage ... cmpctblock 8 passed.

fuzz: reset connman state in p2p targets

Clear ConnmanTestMsg state after stopping test nodes in cmpctblock and
p2p_handshake so sticky CConnman state does not leak between fuzz inputs.

fd403f9474

DrahtBot added the label Fuzzing on Jul 26, 2026
DrahtBot commented at 11:23 AM on July 26, 2026: contributor



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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35808.



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Concept ACK nervana21

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in src/test/fuzz/p2p_handshake.cpp:109 in fd403f9474
```
 105 | @@ -106,4 +106,5 @@ FUZZ_TARGET(p2p_handshake, .init = ::initialize)
 106 |      }
 107 |  
 108 |      node.connman->StopNodes();
 109 | +    connman.Reset();
```
nervana21 commented at 6:26 PM on August 8, 2026:

fd403f947432067678a9d5e866d06df3e59ad0e1: fuzz: reset connman state in p2p targets

All other fuzz callers of connman.Reset() are at the start of the input (process_message.cpp, process_messages.cpp, p2p_private_broadcast.cpp).

Is there a good reason to abandon that pattern here? If not, I'd prefer moving this Reset call to the start of the harness to stay consistent with the rest of the codebase.
nervana21 commented at 6:26 PM on August 8, 2026: contributor

Concept ACK

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Concept ACK	nervana21

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fuzz: reset connman state in p2p targets #35808

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