Merge bitcoin/bitcoin#26306: add lock annotation for FeeFilterRounder::round()

cbb2da8 add lock annotation for FeeFilterRounder::round() (glozow)

Pull request description:

  CI failure from #24407: https://github.com/bitcoin/bitcoin/runs/8876014446

  Calling `WITH_LOCK()` on a non-recursive mutex requires not holding it beforehand.

ACKs for top commit:
  achow101:
    ACK cbb2da8
  dergoegge:
    ACK cbb2da8
  hebasto:
    ACK cbb2da8, tested on Ubuntu 22.04 with clang 14.0.

Tree-SHA512: d6782ee48442b9d64d58a54c1ec7c53822ab051bf9728b44d6a0e05f1953e90f16420d349379345845db203fbad4e1f5750d9070adcb7daa18f12359a29488ca

Author: achow101

src/policy/fees.cpp

@@ -1036,6 +1036,7 @@ FeeFilterRounder::FeeFilterRounder(const CFeeRate& minIncrementalFee)
 
 CAmount FeeFilterRounder::round(CAmount currentMinFee)
 {
+    AssertLockNotHeld(m_insecure_rand_mutex);
     std::set<double>::iterator it = m_fee_set.lower_bound(currentMinFee);
     if (it == m_fee_set.end() ||
         (it != m_fee_set.begin() &&

src/policy/fees.h

@@ -302,7 +302,7 @@ class FeeFilterRounder
     explicit FeeFilterRounder(const CFeeRate& min_incremental_fee);
 
     /** Quantize a minimum fee for privacy purpose before broadcast. */
-    CAmount round(CAmount currentMinFee);
+    CAmount round(CAmount currentMinFee) EXCLUSIVE_LOCKS_REQUIRED(!m_insecure_rand_mutex);
 
 private:
     const std::set<double> m_fee_set;