Merge #16127: More thread safety annotation coverage

5478d6c099e76fe070703cc5383cba7b91468b0f logging: thread safety annotations (Anthony Towns)
e685ca19928eec4e687c66f5edfcfff085a42c27 util/system.cpp: add thread safety annotations for dir_locks (Anthony Towns)
a7887899480db72328784009181d93904e6d479d test/checkqueue_tests: thread safety annotations (Anthony Towns)
479c5846f7477625ec275fbb8a076c7ef157172b rpc/blockchain.cpp: thread safety annotations for latestblock (Anthony Towns)
8b5af3d4c1270267ad85e78f661bf8fab06f3aad net: fMsgProcWake use LOCK instead of lock_guard (Anthony Towns)
de7c5f41aba860751ef7824245e6d9d5088a1200 wallet/wallet.h: Remove mutexScanning which was only protecting a single atomic bool (Anthony Towns)
c3cf2f55013c4ea1c1ef4a878fc7ff8e92f2c42d rpc/blockchain.cpp: Remove g_utxosetscan mutex that is only protecting a single atomic variable (Anthony Towns)

Pull request description:

  In a few cases we need to use `std::mutex` rather than the sync.h primitives. But `std::lock_guard<std::mutex>` doesn't include the clang thread safety annotations unless you also use clang's C library, which means you can't indicate when variables should be guarded by `std::mutex` mutexes.

  This adds an annotated version of `std::lock_guard<std::mutex>` to threadsafety.h to fix that, and modifies places where `std::mutex` is used to take advantage of the annotations.

  It's based on top of #16112, and turns the thread safety comments included there into annotations.

  It also changes the RAII classes in wallet/wallet.h and rpc/blockchain.cpp to just use the atomic<bool> flag for synchronisation rather than having a mutex that doesn't actually guard anything as well.

ACKs for top commit:
  MarcoFalke:
    ACK 5478d6c099e76fe070703cc5383cba7b91468b0f 🗾
  hebasto:
    re-ACK 5478d6c099e76fe070703cc5383cba7b91468b0f, only renamed s/`MutexGuard`/`LockGuard`/, and dropped the commit "test/util_threadnames_tests: add thread safety annotations" since the [previous](https://github.com/bitcoin/bitcoin/pull/16127#pullrequestreview-414184113) review.
  ryanofsky:
    Code review ACK 5478d6c099e76fe070703cc5383cba7b91468b0f. Thanks for taking suggestions! Only changes since last review are dropping thread rename test commit d53072ec730d8eec5a5b72f7e65a54b141e62b19 and renaming mutex guard to lock guard

Tree-SHA512: 7b00d31f6f2b5a222ec69431eb810a74abf0542db3a65d1bbad54e354c40df2857ec89c00b4a5e466c81ba223267ca95f3f98d5fbc1a1d052a2c3a7d2209790a

1 files changed, 14 insertions, 9 deletions

diff --git a/src/test/checkqueue_tests.cpp b/src/test/checkqueue_tests.cpp
index 0565982215..35750b2ebc 100644
--- a/src/test/checkqueue_tests.cpp
+++ b/src/test/checkqueue_tests.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <checkqueue.h>
+#include <sync.h>
 #include <test/util/setup_common.h>
 #include <util/memory.h>
 #include <util/system.h>
@@ -57,14 +58,14 @@ struct FailingCheck {
 };
 
 struct UniqueCheck {
-    static std::mutex m;
-    static std::unordered_multiset<size_t> results;
+    static Mutex m;
+    static std::unordered_multiset<size_t> results GUARDED_BY(m);
     size_t check_id;
     UniqueCheck(size_t check_id_in) : check_id(check_id_in){};
     UniqueCheck() : check_id(0){};
     bool operator()()
     {
-        std::lock_guard<std::mutex> l(m);
+        LOCK(m);
         results.insert(check_id);
         return true;
     }
@@ -127,7 +128,7 @@ struct FrozenCleanupCheck {
 std::mutex FrozenCleanupCheck::m{};
 std::atomic<uint64_t> FrozenCleanupCheck::nFrozen{0};
 std::condition_variable FrozenCleanupCheck::cv{};
-std::mutex UniqueCheck::m;
+Mutex UniqueCheck::m;
 std::unordered_multiset<size_t> UniqueCheck::results;
 std::atomic<size_t> FakeCheckCheckCompletion::n_calls{0};
 std::atomic<size_t> MemoryCheck::fake_allocated_memory{0};
@@ -290,11 +291,15 @@ BOOST_AUTO_TEST_CASE(test_CheckQueue_UniqueCheck)
             control.Add(vChecks);
         }
     }
-    bool r = true;
-    BOOST_REQUIRE_EQUAL(UniqueCheck::results.size(), COUNT);
-    for (size_t i = 0; i < COUNT; ++i)
-        r = r && UniqueCheck::results.count(i) == 1;
-    BOOST_REQUIRE(r);
+    {
+        LOCK(UniqueCheck::m);
+        bool r = true;
+        BOOST_REQUIRE_EQUAL(UniqueCheck::results.size(), COUNT);
+        for (size_t i = 0; i < COUNT; ++i) {
+            r = r && UniqueCheck::results.count(i) == 1;
+        }
+        BOOST_REQUIRE(r);
+    }
     tg.interrupt_all();
     tg.join_all();
 }