diff options
author | Mathieu Chartier <mathieuc@google.com> | 2014-10-15 16:59:47 -0700 |
---|---|---|
committer | Mathieu Chartier <mathieuc@google.com> | 2014-10-16 19:16:41 -0700 |
commit | d000480134b7b00895fbfd142f1d1e18d9cfa6e9 (patch) | |
tree | a9fab808555310308aecda2a59a7c90727ede0ff | |
parent | d866c7616cb3426c431b635ae69964ce69c2ecb5 (diff) | |
download | art-d000480134b7b00895fbfd142f1d1e18d9cfa6e9.zip art-d000480134b7b00895fbfd142f1d1e18d9cfa6e9.tar.gz art-d000480134b7b00895fbfd142f1d1e18d9cfa6e9.tar.bz2 |
Add way to ensure we are at the front of the sigaction chain
Calling this after jni_on_load fixes the unity apps. This is
not exactly correct since we may already have the following chain.
Start up:
Us -> debuggerd
After app goes in front:
App -> us -> debuggerd
After we put ourself back at the front:
Us -> app -> us -> app -> .... stack overflow.
Bug: 17620677
Change-Id: I9183997e3d5ebd51c320b5d51425be5142e938f3
(cherry picked from commit 1f24296c7c8a6501ee2388c0d20b48f471b48660)
-rw-r--r-- | runtime/fault_handler.cc | 26 | ||||
-rw-r--r-- | runtime/fault_handler.h | 2 | ||||
-rw-r--r-- | runtime/java_vm_ext.cc | 5 | ||||
-rw-r--r-- | runtime/jni_internal.cc | 1 | ||||
-rw-r--r-- | sigchainlib/sigchain.cc | 22 | ||||
-rw-r--r-- | sigchainlib/sigchain.h | 6 | ||||
-rw-r--r-- | sigchainlib/sigchain_dummy.cc | 5 | ||||
-rw-r--r-- | sigchainlib/version-script.txt | 1 |
8 files changed, 56 insertions, 12 deletions
diff --git a/runtime/fault_handler.cc b/runtime/fault_handler.cc index fede2f8..62e0609 100644 --- a/runtime/fault_handler.cc +++ b/runtime/fault_handler.cc @@ -95,16 +95,29 @@ FaultManager::FaultManager() : initialized_(false) { FaultManager::~FaultManager() { } +static void SetUpArtAction(struct sigaction* action) { + action->sa_sigaction = art_fault_handler; + sigemptyset(&action->sa_mask); + action->sa_flags = SA_SIGINFO | SA_ONSTACK; +#if !defined(__APPLE__) && !defined(__mips__) + action->sa_restorer = nullptr; +#endif +} + +void FaultManager::EnsureArtActionInFrontOfSignalChain() { + if (initialized_) { + struct sigaction action; + SetUpArtAction(&action); + EnsureFrontOfChain(SIGSEGV, &action); + } else { + LOG(WARNING) << "Can't call " << __FUNCTION__ << " due to unitialized fault manager"; + } +} void FaultManager::Init() { CHECK(!initialized_); struct sigaction action; - action.sa_sigaction = art_fault_handler; - sigemptyset(&action.sa_mask); - action.sa_flags = SA_SIGINFO | SA_ONSTACK; -#if !defined(__APPLE__) && !defined(__mips__) - action.sa_restorer = nullptr; -#endif + SetUpArtAction(&action); // Set our signal handler now. int e = sigaction(SIGSEGV, &action, &oldaction_); @@ -138,7 +151,6 @@ void FaultManager::HandleFault(int sig, siginfo_t* info, void* context) { // // If malloc calls abort, it will be holding its lock. // If the handler tries to call malloc, it will deadlock. - VLOG(signals) << "Handling fault"; if (IsInGeneratedCode(info, context, true)) { VLOG(signals) << "in generated code, looking for handler"; diff --git a/runtime/fault_handler.h b/runtime/fault_handler.h index 8b66a6f..adac4c2 100644 --- a/runtime/fault_handler.h +++ b/runtime/fault_handler.h @@ -45,6 +45,7 @@ class FaultManager { // Unclaim signals and delete registered handlers. void Shutdown(); + void EnsureArtActionInFrontOfSignalChain(); void HandleFault(int sig, siginfo_t* info, void* context); void HandleNestedSignal(int sig, siginfo_t* info, void* context); @@ -128,7 +129,6 @@ class JavaStackTraceHandler FINAL : public FaultHandler { DISALLOW_COPY_AND_ASSIGN(JavaStackTraceHandler); }; - // Statically allocated so the the signal handler can Get access to it. extern FaultManager fault_manager; diff --git a/runtime/java_vm_ext.cc b/runtime/java_vm_ext.cc index 1444d97..fed8bf0 100644 --- a/runtime/java_vm_ext.cc +++ b/runtime/java_vm_ext.cc @@ -21,6 +21,7 @@ #include "base/mutex.h" #include "base/stl_util.h" #include "check_jni.h" +#include "fault_handler.h" #include "indirect_reference_table-inl.h" #include "mirror/art_method.h" #include "mirror/class-inl.h" @@ -688,6 +689,10 @@ bool JavaVMExt::LoadNativeLibrary(JNIEnv* env, const std::string& path, jobject JNI_OnLoadFn jni_on_load = reinterpret_cast<JNI_OnLoadFn>(sym); int version = (*jni_on_load)(this, nullptr); + if (runtime_->GetTargetSdkVersion() != 0 && runtime_->GetTargetSdkVersion() <= 21) { + fault_manager.EnsureArtActionInFrontOfSignalChain(); + } + self->SetClassLoaderOverride(old_class_loader.get()); if (version == JNI_ERR) { diff --git a/runtime/jni_internal.cc b/runtime/jni_internal.cc index dea3014..361ab8d 100644 --- a/runtime/jni_internal.cc +++ b/runtime/jni_internal.cc @@ -30,6 +30,7 @@ #include "base/stl_util.h" #include "class_linker-inl.h" #include "dex_file-inl.h" +#include "fault_handler.h" #include "gc_root.h" #include "gc/accounting/card_table-inl.h" #include "indirect_reference_table-inl.h" diff --git a/sigchainlib/sigchain.cc b/sigchainlib/sigchain.cc index c5015e8..601e321 100644 --- a/sigchainlib/sigchain.cc +++ b/sigchainlib/sigchain.cc @@ -35,6 +35,8 @@ namespace art { +typedef int (*SigActionFnPtr)(int, const struct sigaction*, struct sigaction*); + class SignalAction { public: SignalAction() : claimed_(false), uses_old_style_(false) { @@ -147,7 +149,20 @@ extern "C" void InvokeUserSignalHandler(int sig, siginfo_t* info, void* context) } } -// These functions are C linkage since they replace the functions in libc. +extern "C" void EnsureFrontOfChain(int signal, struct sigaction* expected_action) { + CheckSignalValid(signal); + // Read the current action without looking at the chain, it should be the expected action. + SigActionFnPtr linked_sigaction = reinterpret_cast<SigActionFnPtr>(linked_sigaction_sym); + struct sigaction current_action; + linked_sigaction(signal, nullptr, ¤t_action); + // If the sigactions don't match then we put the current action on the chain and make ourself as + // the main action. + if (current_action.sa_sigaction != expected_action->sa_sigaction) { + log("Warning: Unexpected sigaction action found %p\n", current_action.sa_sigaction); + user_sigactions[signal].Claim(current_action); + linked_sigaction(signal, expected_action, nullptr); + } +} extern "C" int sigaction(int signal, const struct sigaction* new_action, struct sigaction* old_action) { // If this signal has been claimed as a signal chain, record the user's @@ -179,9 +194,7 @@ extern "C" int sigaction(int signal, const struct sigaction* new_action, struct log("Unable to find next sigaction in signal chain"); abort(); } - - typedef int (*SigAction)(int, const struct sigaction*, struct sigaction*); - SigAction linked_sigaction = reinterpret_cast<SigAction>(linked_sigaction_sym); + SigActionFnPtr linked_sigaction = reinterpret_cast<SigActionFnPtr>(linked_sigaction_sym); return linked_sigaction(signal, new_action, old_action); } @@ -287,5 +300,6 @@ extern "C" void InitializeSignalChain() { } initialized = true; } + } // namespace art diff --git a/sigchainlib/sigchain.h b/sigchainlib/sigchain.h index 0de0d08..79b76a7 100644 --- a/sigchainlib/sigchain.h +++ b/sigchainlib/sigchain.h @@ -19,6 +19,8 @@ #include <signal.h> +namespace art { + extern "C" void InitializeSignalChain(); extern "C" void ClaimSignalChain(int signal, struct sigaction* oldaction); @@ -27,4 +29,8 @@ extern "C" void UnclaimSignalChain(int signal); extern "C" void InvokeUserSignalHandler(int sig, siginfo_t* info, void* context); +extern "C" void EnsureFrontOfChain(int signal, struct sigaction* expected_action); + +} // namespace art + #endif // ART_SIGCHAINLIB_SIGCHAIN_H_ diff --git a/sigchainlib/sigchain_dummy.cc b/sigchainlib/sigchain_dummy.cc index 7176f05..fbc8c3f 100644 --- a/sigchainlib/sigchain_dummy.cc +++ b/sigchainlib/sigchain_dummy.cc @@ -57,3 +57,8 @@ extern "C" void InitializeSignalChain() { log("InitializeSignalChain is not exported by the main executable."); abort(); } + +extern "C" void EnsureFrontOfChain(int signal, struct sigaction* expected_action) { + log("EnsureFrontOfChain is not exported by the main executable."); + abort(); +} diff --git a/sigchainlib/version-script.txt b/sigchainlib/version-script.txt index 8030da4..ce15054 100644 --- a/sigchainlib/version-script.txt +++ b/sigchainlib/version-script.txt @@ -4,6 +4,7 @@ global: UnclaimSignalChain; InvokeUserSignalHandler; InitializeSignalChain; + EnsureFrontOfChain; sigaction; signal; sigprocmask; |