Index: lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -1697,6 +1697,12 @@
   if (G->hasSection()) {
     StringRef Section = G->getSection();
 
+    // There are many non-default sections in the kernel, many of which contain
+    // arrays of structures and pointers, which are merged together and
+    // traversed at runtime. Instrumenting them would break the kernel.
+    if (CompileKernel)
+      return false;
+
     // Globals from llvm.metadata aren't emitted, do not instrument them.
     if (Section == "llvm.metadata") return false;
     // Do not instrument globals from special LLVM sections.
@@ -2251,7 +2257,9 @@
       (UseGlobalsGC && TargetTriple.isOSBinFormatELF()) ? getUniqueModuleId(&M)
                                                         : "";
 
-  if (!ELFUniqueModuleId.empty()) {
+  // Clang emits invalid flags for section directives when trying to instrument
+  // kernel globals with InstrumentGlobalsELF().
+  if (!ELFUniqueModuleId.empty() && !CompileKernel) {
     InstrumentGlobalsELF(IRB, M, NewGlobals, Initializers, ELFUniqueModuleId);
     *CtorComdat = true;
   } else if (UseGlobalsGC && TargetTriple.isOSBinFormatCOFF()) {
@@ -2288,20 +2296,22 @@
   Mapping = getShadowMapping(TargetTriple, LongSize, CompileKernel);
   initializeCallbacks(M);
 
-  if (CompileKernel)
-    return false;
+  // No need to emit __asan_init and __asan_version_mismatch_check_vXX for the
+  // kernel.
+  std::string VersionCheckName =
+      CompileKernel
+          ? ""
+          : kAsanVersionCheckNamePrefix + std::to_string(GetAsanVersion(M));
+  std::string InitName = CompileKernel ? "" : kAsanInitName;
 
   // Create a module constructor. A destructor is created lazily because not all
   // platforms, and not all modules need it.
-  std::string VersionCheckName =
-      kAsanVersionCheckNamePrefix + std::to_string(GetAsanVersion(M));
   std::tie(AsanCtorFunction, std::ignore) = createSanitizerCtorAndInitFunctions(
-      M, kAsanModuleCtorName, kAsanInitName, /*InitArgTypes=*/{},
+      M, kAsanModuleCtorName, InitName, /*InitArgTypes=*/{},
       /*InitArgs=*/{}, VersionCheckName);
 
   bool CtorComdat = true;
   bool Changed = false;
-  // TODO(glider): temporarily disabled globals instrumentation for KASan.
   if (ClGlobals) {
     IRBuilder<> IRB(AsanCtorFunction->getEntryBlock().getTerminator());
     Changed |= InstrumentGlobals(IRB, M, &CtorComdat);
@@ -2311,9 +2321,13 @@
   // (1) global instrumentation is not TU-specific
   // (2) target is ELF.
   if (UseCtorComdat && TargetTriple.isOSBinFormatELF() && CtorComdat) {
-    AsanCtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleCtorName));
-    appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority,
-                        AsanCtorFunction);
+    // When building the kernel, don't emit the constructor if there're no
+    // globals.
+    if (!CompileKernel || Changed) {
+      AsanCtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleCtorName));
+      appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority,
+                          AsanCtorFunction);
+    }
     if (AsanDtorFunction) {
       AsanDtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleDtorName));
       appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority,
Index: lib/Transforms/Utils/ModuleUtils.cpp
===================================================================
--- lib/Transforms/Utils/ModuleUtils.cpp
+++ lib/Transforms/Utils/ModuleUtils.cpp
@@ -155,14 +155,17 @@
   assert(!InitName.empty() && "Expected init function name");
   assert(InitArgs.size() == InitArgTypes.size() &&
          "Sanitizer's init function expects different number of arguments");
-  Function *InitFunction =
-      declareSanitizerInitFunction(M, InitName, InitArgTypes);
+  Function *InitFunction = nullptr;
+
   Function *Ctor = Function::Create(
       FunctionType::get(Type::getVoidTy(M.getContext()), false),
       GlobalValue::InternalLinkage, CtorName, &M);
   BasicBlock *CtorBB = BasicBlock::Create(M.getContext(), "", Ctor);
   IRBuilder<> IRB(ReturnInst::Create(M.getContext(), CtorBB));
-  IRB.CreateCall(InitFunction, InitArgs);
+  if (!InitName.empty()) {
+    InitFunction = declareSanitizerInitFunction(M, InitName, InitArgTypes);
+    IRB.CreateCall(InitFunction, InitArgs);
+  }
   if (!VersionCheckName.empty()) {
     Function *VersionCheckFunction =
         checkSanitizerInterfaceFunction(M.getOrInsertFunction(
Index: test/Instrumentation/AddressSanitizer/adaptive_global_redzones.ll
===================================================================
--- test/Instrumentation/AddressSanitizer/adaptive_global_redzones.ll
+++ test/Instrumentation/AddressSanitizer/adaptive_global_redzones.ll
@@ -1,5 +1,6 @@
 ; RUN: opt < %s -asan -asan-module -S | FileCheck %s
 ; RUN: opt < %s -asan -asan-module -asan-mapping-scale=5 -S | FileCheck %s
+; RUN: opt < %s -asan -asan-module -asan-kernel=1 -S | FileCheck %s
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-unknown-linux-gnu"