diff --git a/clang-tools-extra/clangd/support/Threading.cpp b/clang-tools-extra/clangd/support/Threading.cpp
--- a/clang-tools-extra/clangd/support/Threading.cpp
+++ b/clang-tools-extra/clangd/support/Threading.cpp
@@ -8,6 +8,7 @@
 
 #include "support/Threading.h"
 #include "support/Trace.h"
+#include "clang/Basic/Stack.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/thread.h"
@@ -98,6 +99,9 @@
   auto Task = [Name = Name.str(), Action = std::move(Action),
                Cleanup = std::move(CleanupTask)]() mutable {
     llvm::set_thread_name(Name);
+    // Mark the bottom of the stack for clang to be aware of the stack usage and
+    // prevent stack overflow.
+    clang::noteBottomOfStack();
     Action();
     // Make sure function stored by ThreadFunc is destroyed before Cleanup runs.
     Action = nullptr;
diff --git a/clang-tools-extra/clangd/test/infinite-instantiation.test b/clang-tools-extra/clangd/test/infinite-instantiation.test
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/test/infinite-instantiation.test
@@ -0,0 +1,13 @@
+// RUN: cp %s %t.cpp
+// RUN: not clangd -check=%t.cpp 2>&1 | FileCheck -strict-whitespace %s
+
+// CHECK: [template_recursion_depth_exceeded]
+
+template <typename... T>
+constexpr int f(T... args) {
+  return f(0, args...);
+}
+
+int main() {
+  auto i = f();
+}
diff --git a/clang-tools-extra/clangd/tool/ClangdMain.cpp b/clang-tools-extra/clangd/tool/ClangdMain.cpp
--- a/clang-tools-extra/clangd/tool/ClangdMain.cpp
+++ b/clang-tools-extra/clangd/tool/ClangdMain.cpp
@@ -29,6 +29,7 @@
 #include "support/ThreadCrashReporter.h"
 #include "support/ThreadsafeFS.h"
 #include "support/Trace.h"
+#include "clang/Basic/Stack.h"
 #include "clang/Format/Format.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
@@ -710,6 +711,9 @@
 };
 
 int clangdMain(int argc, char *argv[]) {
+  // Clang could run on the main thread. e.g., when the flag '-check' or '-sync'
+  // is enabled.
+  clang::noteBottomOfStack();
   llvm::InitializeAllTargetInfos();
   llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
   llvm::sys::AddSignalHandler(
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -15,6 +15,7 @@
 #include "clang/Basic/FileEntry.h"
 #include "clang/Basic/LangStandard.h"
 #include "clang/Basic/Sarif.h"
+#include "clang/Basic/Stack.h"
 #include "clang/Frontend/ASTUnit.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
@@ -1155,6 +1156,10 @@
   CompilerInstance &CI = getCompilerInstance();
   if (!CI.hasPreprocessor())
     return;
+  // This is a fallback: If the client forgets to invoke this, we mark the
+  // current stack as the bottom. Though not optimal, this could help prevent
+  // stack overflow during deep recursion.
+  clang::noteBottomOfStack();
 
   // FIXME: Move the truncation aspect of this into Sema, we delayed this till
   // here so the source manager would be initialized.