Merge bitcoin/bitcoin#26036: net: add NetEventsInterface::g_msgproc_mutex

d575a675cc884b1bebdb6197f2ef45c51788d4a3 net_processing: add thread safety annotation for m_highest_fast_announce (Anthony Towns)
0ae7987f68211729d87c9255889f4d9d1aa6a37f net_processing: add thread safety annotations for PeerManagerImpl members accessed only via the msgproc thread (Anthony Towns)
a66a7ccb822f0f1f554d27d04735b7fb585d3b71 net_processing: add thread safety annotations for Peer members accessed only via the msgproc thread (Anthony Towns)
bf12abe4542f2cf658516ea7e7fbbff6864c2208 net: drop cs_sendProcessing (Anthony Towns)
1e78f566d575a047a6f0b762bc79601e0208d103 net: add NetEventsInterface::g_msgproc_mutex (Anthony Towns)

Pull request description:

  There are many cases where we assume message processing is single-threaded in order for how we access node-related memory to be safe. Add an explicit mutex that we can use to document this, which allows the compiler to catch any cases where we try to access that memory from other threads and break that assumption.

ACKs for top commit:
  MarcoFalke:
    review ACK d575a675cc884b1bebdb6197f2ef45c51788d4a3 📽
  dergoegge:
    Code review ACK d575a675cc884b1bebdb6197f2ef45c51788d4a3
  w0xlt:
    ACK https://github.com/bitcoin/bitcoin/pull/26036/commits/d575a675cc884b1bebdb6197f2ef45c51788d4a3
  vasild:
    ACK d575a675cc884b1bebdb6197f2ef45c51788d4a3 modulo the missing runtime checks

Tree-SHA512: b886d1aa4adf318ae64e32ccaf3d508dbb79d6eed3f1fa9d8b2ed96f3c72a3d38cd0f12e05826c9832a2a1302988adfd2b43ea9691aa844f37d8f5c37ff20e05

1 files changed, 5 insertions, 4 deletions

diff --git a/src/net.cpp b/src/net.cpp
index 0cc14b1d2a..b194be3265 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -1991,8 +1991,12 @@ void CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFai
     }
 }
 
+Mutex NetEventsInterface::g_msgproc_mutex;
+
 void CConnman::ThreadMessageHandler()
 {
+    LOCK(NetEventsInterface::g_msgproc_mutex);
+
     SetSyscallSandboxPolicy(SyscallSandboxPolicy::MESSAGE_HANDLER);
     while (!flagInterruptMsgProc)
     {
@@ -2014,10 +2018,7 @@ void CConnman::ThreadMessageHandler()
                 if (flagInterruptMsgProc)
                     return;
                 // Send messages
-                {
-                    LOCK(pnode->cs_sendProcessing);
-                    m_msgproc->SendMessages(pnode);
-                }
+                m_msgproc->SendMessages(pnode);
 
                 if (flagInterruptMsgProc)
                     return;