diff --git a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
--- a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -58,6 +58,7 @@
 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicSize.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
@@ -389,6 +390,13 @@
   // TODO: Remove mutable by moving the initializtaion to the registry function.
   mutable Optional<uint64_t> KernelZeroFlagVal;
 
+  // This type stores obtained value of macro `ZERO_SIZE_PTR`, and if it could
+  // be obtained.
+  using KernelZeroSizePtrValueTy = Optional<int>;
+  /// Store the optional value of macro called `ZERO_SIZE_PTR`.
+  /// The value is initialized at first use.
+  mutable Optional<KernelZeroSizePtrValueTy> KernelZeroSizePtrValue;
+
   /// Process C++ operator new()'s allocation, which is the part of C++
   /// new-expression that goes before the constructor.
   void processNewAllocation(const CXXNewExpr *NE, CheckerContext &C,
@@ -658,6 +666,13 @@
                                     CheckerContext &C);
 
   void reportLeak(SymbolRef Sym, ExplodedNode *N, CheckerContext &C) const;
+
+  void initKernelZeroSizePtrValue(Preprocessor &PP) const {
+    // If not initialized yet,
+    if (!KernelZeroSizePtrValue)
+      // try to get the value.
+      KernelZeroSizePtrValue = tryExpandAsInteger("ZERO_SIZE_PTR", PP);
+  }
 };
 
 //===----------------------------------------------------------------------===//
@@ -1672,6 +1687,18 @@
   if (ArgVal.isUnknownOrUndef())
     return nullptr;
 
+  // If there is a macro called ZERO_SIZE_PTR, it could be a kernel source code
+  // and this value indicates a special value used for a zero-sized memory
+  // block. It is a constant value that is allowed to be freed.
+  const llvm::APSInt *ArgValKnown =
+      C.getSValBuilder().getKnownValue(State, ArgVal);
+  if (ArgValKnown) {
+    initKernelZeroSizePtrValue(C.getPreprocessor());
+    if (*KernelZeroSizePtrValue &&
+        ArgValKnown->getSExtValue() == **KernelZeroSizePtrValue)
+      return nullptr;
+  }
+
   const MemRegion *R = ArgVal.getAsRegion();
 
   // Nonlocs can't be freed, of course.
diff --git a/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp b/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp
--- a/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp
@@ -126,9 +126,6 @@
     if (!T.isOneOf(tok::l_paren, tok::r_paren))
       FilteredTokens.push_back(T);
 
-  if (FilteredTokens.size() > 2)
-    return llvm::None;
-
   // Parse an integer at the end of the macro definition.
   const Token &T = FilteredTokens.back();
   if (!T.isLiteral())
@@ -140,11 +137,10 @@
     return llvm::None;
 
   // Parse an optional minus sign.
-  if (FilteredTokens.size() == 2) {
-    if (FilteredTokens.front().is(tok::minus))
+  size_t Size = FilteredTokens.size();
+  if (Size >= 2) {
+    if (FilteredTokens[Size - 2].is(tok::minus))
       IntValue = -IntValue;
-    else
-      return llvm::None;
   }
 
   return IntValue.getSExtValue();
diff --git a/clang/test/Analysis/kmalloc-linux-1.c b/clang/test/Analysis/kmalloc-linux-1.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Analysis/kmalloc-linux-1.c
@@ -0,0 +1,27 @@
+// RUN: %clang_analyze_cc1 -triple x86_64-unknown-linux -analyzer-checker=unix.Malloc -verify %s
+
+#define ZERO_SIZE_PTR ((void *)16)
+
+void *__kmalloc(int size, int flags);
+
+// Linux kmalloc looks like this.
+// (simplified)
+void *kmalloc(int size, int flags) {
+  if (size == 0)
+    return ZERO_SIZE_PTR;
+  return __kmalloc(size, flags);
+}
+
+// FIXME: malloc checker expects kfree with 2 arguments, is this correct?
+// (recent kernel source code contains a `kfree(const void *)`)
+void kfree(void *, int);
+
+void test_kmalloc_zero_sized_block_fixed_value_address() {
+  void *ptr = kmalloc(0, 0); // kmalloc returns a constant address
+  kfree(ptr, 0);             // no warning about freeing a constant value
+}
+
+void test_kfree_constant_value() {
+  void *ptr = (void *)1;
+  kfree(ptr, 0); // expected-warning{{Argument to kfree() is a constant address (1)}}
+}