From 69b550d91a8f4e864fa98d22a3bcd6158b2f6962 Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Sun, 24 May 2020 17:11:56 -0400
Subject: [PATCH] Fix crash on shutdown with snapshots pending

Former-commit-id: 124e79a81d6995ea7d5ba39d1830b591b705acbf
---
 src/db.cpp     | 4 ++--
 src/evict.cpp  | 2 +-
 src/server.cpp | 6 ++++++
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/db.cpp b/src/db.cpp
index 7fde78da1..fdb167dec 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -2463,8 +2463,8 @@ void redisDbPersistentData::commitChanges()
 
 redisDbPersistentData::~redisDbPersistentData()
 {
-    if (m_pdbSnapshotASYNC)
-        endSnapshot(m_pdbSnapshotASYNC);
+    if (m_spdbSnapshotHOLDER != nullptr)
+        endSnapshot(m_spdbSnapshotHOLDER.get());
     
     //serverAssert(m_pdbSnapshot == nullptr);
     serverAssert(m_refCount == 0);
diff --git a/src/evict.cpp b/src/evict.cpp
index e15ddb6cc..8429ea3db 100644
--- a/src/evict.cpp
+++ b/src/evict.cpp
@@ -721,6 +721,6 @@ cant_free:
  *
  */
 int freeMemoryIfNeededAndSafe(bool fPreSnapshot) {
-    if (g_pserver->lua_timedout || g_pserver->loading) return C_OK;
+    if (g_pserver->shutdown_asap || g_pserver->lua_timedout || g_pserver->loading) return C_OK;
     return freeMemoryIfNeeded(fPreSnapshot);
 }
diff --git a/src/server.cpp b/src/server.cpp
index 55eb41828..5c53d7157 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -5926,10 +5926,16 @@ int main(int argc, char **argv) {
         pthread_join(rgthread[iel], &pvRet);
 
     /* free our databases */
+    bool fLockAcquired = aeTryAcquireLock(false);
+    g_pserver->shutdown_asap = true;    // flag that we're in shutdown
+    if (!fLockAcquired)
+        g_fInCrash = true;  // We don't actually crash right away, because we want to sync any storage providers
     for (int idb = 0; idb < cserver.dbnum; ++idb) {
         delete g_pserver->db[idb];
         g_pserver->db[idb] = nullptr;
     }
+    // If we couldn't acquire the global lock it means something wasn't shutdown and we'll probably deadlock
+    serverAssert(fLockAcquired);
 
     g_pserver->garbageCollector.shutdown();
     delete g_pserver->m_pstorageFactory;