b396467053 locks: Annotate CTxMemPool::check to require cs_main (Carl Dong)
Pull request description:
```
Currently, CTxMemPool::check locks CTxMemPool's own cs member, then
calls GetSpendHeight which locks cs_main. This can potentially cause an
undesirable lock invesion since CTxMemPool's cs is supposed to be locked
after cs_main.
This does not cause us any problems right now because all callers of
CTxMemPool already lock cs_main before calling CTxMemPool::check, which
means that the LOCK(cs_main) in GetSpendHeight becomes benign.
However, it is currently possible for new code to be added which calls
CTxMemPool::check without locking cs_main (which would be dangerous).
Therefore we should make it explicit that cs_main needs to be held
before calling CTxMemPool::check.
NOTE: After all review-only assertions are removed in "#20158 |
tree-wide: De-globalize ChainstateManager", and assuming that we
keep the changes in "validation: Pass in spendheight to
CTxMemPool::check", we can re-evaluate to see if this annotation
is still necessary.
```
-----
Previous discussions:
1. https://github.com/bitcoin/bitcoin/pull/20158#discussion_r520639845
2. https://github.com/bitcoin/bitcoin/pull/20158#pullrequestreview-557117202
3. https://github.com/bitcoin/bitcoin/pull/20749#discussion_r559425521
ACKs for top commit:
jnewbery:
Code review ACK b396467053
MarcoFalke:
ACK b396467053
jonatack:
ACK b396467053 review and debug built, verified that `cs_main` is held by callers of `CTxMemPool::check()` in `PeerManagerImpl::ProcessOrphanTx()`, `PeerManagerImpl::ProcessMessage()`, and `CChainState::ActivateBestChainStep()`
Tree-SHA512: 4635cddb4aa1af9532bb657b2f9c4deec4568d16ba28c574eae91bb77368cd40e23c3c720a9de11cec78e7ad678a44a5e25af67f13214b86b56e777e0c35a026
1f45e85509