[clang] c6ec352 - Revert "[KernelAddressSanitizer] Make globals constructors compatible with kernel"

Marco Elver via cfe-commits cfe-commits at lists.llvm.org
Mon Jun 8 01:37:36 PDT 2020


Author: Marco Elver
Date: 2020-06-08T10:34:03+02:00
New Revision: c6ec352a6bde1995794c523adc2ebab802ccdf0a

URL: https://github.com/llvm/llvm-project/commit/c6ec352a6bde1995794c523adc2ebab802ccdf0a
DIFF: https://github.com/llvm/llvm-project/commit/c6ec352a6bde1995794c523adc2ebab802ccdf0a.diff

LOG: Revert "[KernelAddressSanitizer] Make globals constructors compatible with kernel"

This reverts commit 866ee2353f7d0224644799d0d1faed53c7f3a06d.

Building the kernel results in modpost failures due to modpost relying
on debug info and inspecting kernel modules' globals:
https://github.com/ClangBuiltLinux/linux/issues/1045#issuecomment-640381783

Added: 
    

Modified: 
    clang/test/CodeGen/asan-globals.cpp
    llvm/include/llvm/Transforms/Utils/ModuleUtils.h
    llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
    llvm/lib/Transforms/Utils/ModuleUtils.cpp

Removed: 
    


################################################################################
diff  --git a/clang/test/CodeGen/asan-globals.cpp b/clang/test/CodeGen/asan-globals.cpp
index a5374caae5c4..93abb0023cfa 100644
--- a/clang/test/CodeGen/asan-globals.cpp
+++ b/clang/test/CodeGen/asan-globals.cpp
@@ -1,59 +1,40 @@
 // RUN: echo "int extra_global;" > %t.extra-source.cpp
 // RUN: echo "global:*blacklisted_global*" > %t.blacklist
-// RUN: %clang_cc1 -include %t.extra-source.cpp -fsanitize=address -fsanitize-blacklist=%t.blacklist -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,ASAN
-// RUN: %clang_cc1 -include %t.extra-source.cpp -fsanitize=kernel-address -fsanitize-blacklist=%t.blacklist -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,KASAN
+// RUN: %clang_cc1 -include %t.extra-source.cpp -fsanitize=address -fsanitize-blacklist=%t.blacklist -emit-llvm -o - %s | FileCheck %s
 // The blacklist file uses regexps, so Windows path backslashes.
 // RUN: echo "src:%s" | sed -e 's/\\/\\\\/g' > %t.blacklist-src
 // RUN: %clang_cc1 -include %t.extra-source.cpp -fsanitize=address -fsanitize-blacklist=%t.blacklist-src -emit-llvm -o - %s | FileCheck %s --check-prefix=BLACKLIST-SRC
-// RUN: %clang_cc1 -include %t.extra-source.cpp -fsanitize=kernel-address -fsanitize-blacklist=%t.blacklist-src -emit-llvm -o - %s | FileCheck %s --check-prefix=BLACKLIST-SRC
 
 int global;
 int dyn_init_global = global;
 int __attribute__((no_sanitize("address"))) attributed_global;
 int blacklisted_global;
-int __attribute__ ((section("__DATA, __common"))) sectioned_global;
 
 void func() {
   static int static_var = 0;
   const char *literal = "Hello, world!";
 }
 
-// CHECK-LABEL: define internal void @asan.module_ctor
-// ASAN-NEXT: call void @__asan_init
-// ASAN-NEXT: call void @__asan_version_mismatch_check
-// KASAN-NOT: call void @__asan_init
-// KASAN-NOT: call void @__asan_version_mismatch_check
-// ASAN-NEXT: call void @__asan_register_globals({{.*}}, i{{32|64}} 6)
-// KASAN-NEXT: call void @__asan_register_globals({{.*}}, i{{32|64}} 5)
-// CHECK-NEXT: ret void
-
-// CHECK-LABEL: define internal void @asan.module_dtor
-// CHECK-NEXT: call void @__asan_unregister_globals
-// CHECK-NEXT: ret void
-
-// CHECK: !llvm.asan.globals = !{![[EXTRA_GLOBAL:[0-9]+]], ![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[ATTR_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[SECTIONED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
+// CHECK: !llvm.asan.globals = !{![[EXTRA_GLOBAL:[0-9]+]], ![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[ATTR_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
 // CHECK: ![[EXTRA_GLOBAL]] = !{{{.*}} ![[EXTRA_GLOBAL_LOC:[0-9]+]], !"extra_global", i1 false, i1 false}
 // CHECK: ![[EXTRA_GLOBAL_LOC]] = !{!"{{.*}}extra-source.cpp", i32 1, i32 5}
 // CHECK: ![[GLOBAL]] = !{{{.*}} ![[GLOBAL_LOC:[0-9]+]], !"global", i1 false, i1 false}
-// CHECK: ![[GLOBAL_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 10, i32 5}
+// CHECK: ![[GLOBAL_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 8, i32 5}
 // CHECK: ![[DYN_INIT_GLOBAL]] = !{{{.*}} ![[DYN_INIT_LOC:[0-9]+]], !"dyn_init_global", i1 true, i1 false}
-// CHECK: ![[DYN_INIT_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 11, i32 5}
+// CHECK: ![[DYN_INIT_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 9, i32 5}
 // CHECK: ![[ATTR_GLOBAL]] = !{{{.*}}, null, null, i1 false, i1 true}
 // CHECK: ![[BLACKLISTED_GLOBAL]] = !{{{.*}}, null, null, i1 false, i1 true}
-// CHECK: ![[SECTIONED_GLOBAL]] = !{{{.*}} ![[SECTIONED_GLOBAL_LOC:[0-9]+]], !"sectioned_global", i1 false, i1 false}
-// CHECK: ![[SECTIONED_GLOBAL_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 14, i32 51}
 // CHECK: ![[STATIC_VAR]] = !{{{.*}} ![[STATIC_LOC:[0-9]+]], !"static_var", i1 false, i1 false}
-// CHECK: ![[STATIC_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 17, i32 14}
+// CHECK: ![[STATIC_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 14, i32 14}
 // CHECK: ![[LITERAL]] = !{{{.*}} ![[LITERAL_LOC:[0-9]+]], !"<string literal>", i1 false, i1 false}
-// CHECK: ![[LITERAL_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 18, i32 25}
+// CHECK: ![[LITERAL_LOC]] = !{!"{{.*}}asan-globals.cpp", i32 15, i32 25}
 
-// BLACKLIST-SRC: !llvm.asan.globals = !{![[EXTRA_GLOBAL:[0-9]+]], ![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[ATTR_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[SECTIONED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
+// BLACKLIST-SRC: !llvm.asan.globals = !{![[EXTRA_GLOBAL:[0-9]+]], ![[GLOBAL:[0-9]+]], ![[DYN_INIT_GLOBAL:[0-9]+]], ![[ATTR_GLOBAL:[0-9]+]], ![[BLACKLISTED_GLOBAL:[0-9]+]], ![[STATIC_VAR:[0-9]+]], ![[LITERAL:[0-9]+]]}
 // BLACKLIST-SRC: ![[EXTRA_GLOBAL]] = !{{{.*}} ![[EXTRA_GLOBAL_LOC:[0-9]+]], !"extra_global", i1 false, i1 false}
 // BLACKLIST-SRC: ![[EXTRA_GLOBAL_LOC]] = !{!"{{.*}}extra-source.cpp", i32 1, i32 5}
 // BLACKLIST-SRC: ![[GLOBAL]] = !{{{.*}} null, null, i1 false, i1 true}
 // BLACKLIST-SRC: ![[DYN_INIT_GLOBAL]] = !{{{.*}} null, null, i1 true, i1 true}
 // BLACKLIST-SRC: ![[ATTR_GLOBAL]] = !{{{.*}}, null, null, i1 false, i1 true}
 // BLACKLIST-SRC: ![[BLACKLISTED_GLOBAL]] = !{{{.*}}, null, null, i1 false, i1 true}
-// BLACKLIST-SRC: ![[SECTIONED_GLOBAL]] = !{{{.*}} null, null, i1 false, i1 true}
 // BLACKLIST-SRC: ![[STATIC_VAR]] = !{{{.*}} null, null, i1 false, i1 true}
 // BLACKLIST-SRC: ![[LITERAL]] = !{{{.*}} null, null, i1 false, i1 true}

diff  --git a/llvm/include/llvm/Transforms/Utils/ModuleUtils.h b/llvm/include/llvm/Transforms/Utils/ModuleUtils.h
index 65added8b7e1..07fbb5b55678 100644
--- a/llvm/include/llvm/Transforms/Utils/ModuleUtils.h
+++ b/llvm/include/llvm/Transforms/Utils/ModuleUtils.h
@@ -42,10 +42,6 @@ void appendToGlobalDtors(Module &M, Function *F, int Priority,
 FunctionCallee declareSanitizerInitFunction(Module &M, StringRef InitName,
                                             ArrayRef<Type *> InitArgTypes);
 
-/// Creates sanitizer constructor function.
-/// \return Returns pointer to constructor.
-Function *createSanitizerCtor(Module &M, StringRef CtorName);
-
 /// Creates sanitizer constructor function, and calls sanitizer's init
 /// function from it.
 /// \return Returns pair of pointers to constructor, and init functions

diff  --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 666b3961eeb0..9c039f0cfcc7 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -589,10 +589,11 @@ struct AddressSanitizer {
   AddressSanitizer(Module &M, const GlobalsMetadata *GlobalsMD,
                    bool CompileKernel = false, bool Recover = false,
                    bool UseAfterScope = false)
-      : CompileKernel(ClEnableKasan.getNumOccurrences() > 0 ? ClEnableKasan
-                                                            : CompileKernel),
-        Recover(ClRecover.getNumOccurrences() > 0 ? ClRecover : Recover),
-        UseAfterScope(UseAfterScope || ClUseAfterScope), GlobalsMD(*GlobalsMD) {
+      : UseAfterScope(UseAfterScope || ClUseAfterScope), GlobalsMD(*GlobalsMD) {
+    this->Recover = ClRecover.getNumOccurrences() > 0 ? ClRecover : Recover;
+    this->CompileKernel =
+        ClEnableKasan.getNumOccurrences() > 0 ? ClEnableKasan : CompileKernel;
+
     C = &(M.getContext());
     LongSize = M.getDataLayout().getPointerSizeInBits();
     IntptrTy = Type::getIntNTy(*C, LongSize);
@@ -741,11 +742,7 @@ class ModuleAddressSanitizer {
   ModuleAddressSanitizer(Module &M, const GlobalsMetadata *GlobalsMD,
                          bool CompileKernel = false, bool Recover = false,
                          bool UseGlobalsGC = true, bool UseOdrIndicator = false)
-      : GlobalsMD(*GlobalsMD),
-        CompileKernel(ClEnableKasan.getNumOccurrences() > 0 ? ClEnableKasan
-                                                            : CompileKernel),
-        Recover(ClRecover.getNumOccurrences() > 0 ? ClRecover : Recover),
-        UseGlobalsGC(UseGlobalsGC && ClUseGlobalsGC && !this->CompileKernel),
+      : GlobalsMD(*GlobalsMD), UseGlobalsGC(UseGlobalsGC && ClUseGlobalsGC),
         // Enable aliases as they should have no downside with ODR indicators.
         UsePrivateAlias(UseOdrIndicator || ClUsePrivateAlias),
         UseOdrIndicator(UseOdrIndicator || ClUseOdrIndicator),
@@ -756,7 +753,11 @@ class ModuleAddressSanitizer {
         // argument is designed as workaround. Therefore, disable both
         // ClWithComdat and ClUseGlobalsGC unless the frontend says it's ok to
         // do globals-gc.
-        UseCtorComdat(UseGlobalsGC && ClWithComdat && !this->CompileKernel) {
+        UseCtorComdat(UseGlobalsGC && ClWithComdat) {
+    this->Recover = ClRecover.getNumOccurrences() > 0 ? ClRecover : Recover;
+    this->CompileKernel =
+        ClEnableKasan.getNumOccurrences() > 0 ? ClEnableKasan : CompileKernel;
+
     C = &(M.getContext());
     int LongSize = M.getDataLayout().getPointerSizeInBits();
     IntptrTy = Type::getIntNTy(*C, LongSize);
@@ -1837,12 +1838,6 @@ bool ModuleAddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
   }
 
   if (G->hasSection()) {
-    // The kernel uses explicit sections for mostly special global variables
-    // that we should not instrument. E.g. the kernel may rely on their layout
-    // without redzones, or remove them at link time ("discard.*"), etc.
-    if (CompileKernel)
-      return false;
-
     StringRef Section = G->getSection();
 
     // Globals from llvm.metadata aren't emitted, do not instrument them.
@@ -2450,23 +2445,20 @@ int ModuleAddressSanitizer::GetAsanVersion(const Module &M) const {
 bool ModuleAddressSanitizer::instrumentModule(Module &M) {
   initializeCallbacks(M);
 
+  if (CompileKernel)
+    return false;
+
   // Create a module constructor. A destructor is created lazily because not all
   // platforms, and not all modules need it.
-  if (CompileKernel) {
-    // The kernel always builds with its own runtime, and therefore does not
-    // need the init and version check calls.
-    AsanCtorFunction = createSanitizerCtor(M, kAsanModuleCtorName);
-  } else {
-    std::string AsanVersion = std::to_string(GetAsanVersion(M));
-    std::string VersionCheckName =
-        ClInsertVersionCheck ? (kAsanVersionCheckNamePrefix + AsanVersion) : "";
-    std::tie(AsanCtorFunction, std::ignore) =
-        createSanitizerCtorAndInitFunctions(M, kAsanModuleCtorName,
-                                            kAsanInitName, /*InitArgTypes=*/{},
-                                            /*InitArgs=*/{}, VersionCheckName);
-  }
+  std::string AsanVersion = std::to_string(GetAsanVersion(M));
+  std::string VersionCheckName =
+      ClInsertVersionCheck ? (kAsanVersionCheckNamePrefix + AsanVersion) : "";
+  std::tie(AsanCtorFunction, std::ignore) = createSanitizerCtorAndInitFunctions(
+      M, kAsanModuleCtorName, kAsanInitName, /*InitArgTypes=*/{},
+      /*InitArgs=*/{}, VersionCheckName);
 
   bool CtorComdat = true;
+  // TODO(glider): temporarily disabled globals instrumentation for KASan.
   if (ClGlobals) {
     IRBuilder<> IRB(AsanCtorFunction->getEntryBlock().getTerminator());
     InstrumentGlobals(IRB, M, &CtorComdat);

diff  --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
index ef9f18a2289e..b2e6d981a622 100644
--- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -119,15 +119,6 @@ llvm::declareSanitizerInitFunction(Module &M, StringRef InitName,
       AttributeList());
 }
 
-Function *llvm::createSanitizerCtor(Module &M, StringRef CtorName) {
-  Function *Ctor = Function::Create(
-      FunctionType::get(Type::getVoidTy(M.getContext()), false),
-      GlobalValue::InternalLinkage, CtorName, &M);
-  BasicBlock *CtorBB = BasicBlock::Create(M.getContext(), "", Ctor);
-  ReturnInst::Create(M.getContext(), CtorBB);
-  return Ctor;
-}
-
 std::pair<Function *, FunctionCallee> llvm::createSanitizerCtorAndInitFunctions(
     Module &M, StringRef CtorName, StringRef InitName,
     ArrayRef<Type *> InitArgTypes, ArrayRef<Value *> InitArgs,
@@ -137,8 +128,11 @@ std::pair<Function *, FunctionCallee> llvm::createSanitizerCtorAndInitFunctions(
          "Sanitizer's init function expects 
diff erent number of arguments");
   FunctionCallee InitFunction =
       declareSanitizerInitFunction(M, InitName, InitArgTypes);
-  Function *Ctor = createSanitizerCtor(M, CtorName);
-  IRBuilder<> IRB(Ctor->getEntryBlock().getTerminator());
+  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 (!VersionCheckName.empty()) {
     FunctionCallee VersionCheckFunction = M.getOrInsertFunction(


        


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