Bug 1856297 - Remove the `CrashAddressLikelyWrong` annotation and its associated machinery r=glandium

Differential Revision: https://phabricator.services.mozilla.com/D189758

js/src/wasm/WasmSignalHandlers.cpp

@@ -801,10 +801,6 @@ static void WasmTrapHandler(int signum, siginfo_t* info, void* context) {
 }
 #  endif  // XP_WIN || XP_DARWIN || assume unix
 
-#  if defined(ANDROID) && defined(MOZ_LINKER)
-extern "C" MFBT_API bool IsSignalHandlingBroken();
-#  endif
-
 struct InstallState {
   bool tried;
   bool success;
@@ -829,13 +825,6 @@ void wasm::EnsureEagerProcessSignalHandlers() {
   eagerInstallState->tried = true;
   MOZ_RELEASE_ASSERT(eagerInstallState->success == false);
 
-#  if defined(ANDROID) && defined(MOZ_LINKER)
-  // Signal handling is broken on some android systems.
-  if (IsSignalHandlingBroken()) {
-    return;
-  }
-#  endif
-
   sAlreadyHandlingTrap.infallibleInit();
 
   // Install whatever exception/signal handler is appropriate for the OS.

mozglue/linker/ElfLoader.cpp

@@ -46,18 +46,7 @@ static int GetAndroidSDKVersion() {
   return version;
 }
 
-#  if __ANDROID_API__ < 8
-/* Android API < 8 doesn't provide sigaltstack */
-
-extern "C" {
-
-inline int sigaltstack(const stack_t* ss, stack_t* oss) {
-  return syscall(__NR_sigaltstack, ss, oss);
-}
-
-} /* extern "C" */
-#  endif /* __ANDROID_API__ */
-#endif   /* ANDROID */
+#endif /* ANDROID */
 
 #ifdef __ARM_EABI__
 extern "C" MOZ_EXPORT const void* __gnu_Unwind_Find_exidx(void* pc, int* pcount)
@@ -315,10 +304,6 @@ MFBT_API void __dl_munmap(void* handle, void* addr, size_t length) {
   return reinterpret_cast<LibHandle*>(handle)->MappableMUnmap(addr, length);
 }
 
-MFBT_API bool IsSignalHandlingBroken() {
-  return ElfLoader::Singleton.isSignalHandlingBroken();
-}
-
 namespace {
 
 /**
@@ -1164,10 +1149,7 @@ struct TmpData {
 };
 
 SEGVHandler::SEGVHandler()
-    : initialized(false),
-      registeredHandler(false),
-      signalHandlingBroken(true),
-      signalHandlingSlow(true) {
+    : initialized(false), registeredHandler(false), signalHandlingSlow(true) {
   /* Ensure logging is initialized before the DEBUG_LOG in the test_handler.
    * As this constructor runs before the ElfLoader constructor (by effect
    * of ElfLoader inheriting from this class), this also initializes on behalf
@@ -1184,14 +1166,9 @@ SEGVHandler::SEGVHandler()
   struct sigaction old_action;
   sys_sigaction(SIGSEGV, nullptr, &old_action);
 
-  /* Some devices don't provide useful information to their SIGSEGV handlers,
-   * making it impossible for on-demand decompression to work. To check if
-   * we're on such a device, setup a temporary handler and deliberately
-   * trigger a segfault. The handler will set signalHandlingBroken if the
-   * provided information is bogus.
-   * Some other devices have a kernel option enabled that makes SIGSEGV handler
+  /* Some devices have a kernel option enabled that makes SIGSEGV handler
    * have an overhead so high that it affects how on-demand decompression
-   * performs. The handler will also set signalHandlingSlow if the triggered
+   * performs. The handler will set signalHandlingSlow if the triggered
    * SIGSEGV took too much time. */
   struct sigaction action;
   action.sa_sigaction = &SEGVHandler::test_handler;
@@ -1217,7 +1194,9 @@ void SEGVHandler::FinishInitialization() {
    * going to race with another thread. */
   initialized = true;
 
-  if (signalHandlingBroken || signalHandlingSlow) return;
+  if (signalHandlingSlow) {
+    return;
+  }
 
   typedef int (*sigaction_func)(int, const struct sigaction*,
                                 struct sigaction*);
@@ -1304,13 +1283,9 @@ SEGVHandler::~SEGVHandler() {
 }
 
 /* Test handler for a deliberately triggered SIGSEGV that determines whether
- * useful information is provided to signal handlers, particularly whether
- * si_addr is filled in properly, and whether the segfault handler is called
- * quickly enough. */
+ * the segfault handler is called quickly enough. */
 void SEGVHandler::test_handler(int signum, siginfo_t* info, void* context) {
   SEGVHandler& that = ElfLoader::Singleton;
-  if (signum == SIGSEGV && info && info->si_addr == that.stackPtr.get())
-    that.signalHandlingBroken = false;
   mprotect(that.stackPtr, that.stackPtr.GetLength(), PROT_READ | PROT_WRITE);
   TmpData* data = reinterpret_cast<TmpData*>(that.stackPtr.get());
   uint64_t latency = ProcessTimeStamp_Now() - data->crash_timestamp;

mozglue/linker/ElfLoader.h

@@ -57,8 +57,6 @@ MFBT_API size_t __dl_get_mappable_length(void* handle);
 MFBT_API void* __dl_mmap(void* handle, void* addr, size_t length, off_t offset);
 
 MFBT_API void __dl_munmap(void* handle, void* addr, size_t length);
-
-MFBT_API bool IsSignalHandlingBroken();
 }
 
 /* Forward declarations for use in LibHandle */
@@ -316,8 +314,6 @@ class SEGVHandler {
     return registeredHandler;
   }
 
-  bool isSignalHandlingBroken() { return signalHandlingBroken; }
-
   static int __wrap_sigaction(int signum, const struct sigaction* act,
                               struct sigaction* oldact);
 
@@ -366,7 +362,6 @@ class SEGVHandler {
 
   bool initialized;
   bool registeredHandler;
-  bool signalHandlingBroken;
   bool signalHandlingSlow;
 };
 

toolkit/crashreporter/CrashAnnotations.yaml

@@ -203,12 +203,6 @@ CPUMicrocodeVersion:
     Version of the CPU microcode.
   type: string
 
-CrashAddressLikelyWrong:
-  description: >
-    Set to 1 if signal handling is broken, in which case the crash address is
-    likely to be wrong.
-  type: boolean
-
 CrashTime:
   description: >
     Crash time in seconds since the Epoch.

toolkit/xre/nsAppRunner.cpp

@@ -344,10 +344,6 @@ nsString gProcessStartupShortcut;
 #endif
 #include "BinaryPath.h"
 
-#ifdef MOZ_LINKER
-extern "C" MFBT_API bool IsSignalHandlingBroken();
-#endif
-
 #ifdef FUZZING
 #  include "FuzzerRunner.h"
 
@@ -4148,11 +4144,6 @@ int XREMain::XRE_mainInit(bool* aExitFlag) {
     nsDependentCString releaseChannel(MOZ_STRINGIFY(MOZ_UPDATE_CHANNEL));
     CrashReporter::AnnotateCrashReport(
         CrashReporter::Annotation::ReleaseChannel, releaseChannel);
-#ifdef MOZ_LINKER
-    CrashReporter::AnnotateCrashReport(
-        CrashReporter::Annotation::CrashAddressLikelyWrong,
-        IsSignalHandlingBroken());
-#endif
 
 #ifdef XP_WIN
     nsAutoString appInitDLLs;