diff options
| -rw-r--r-- | src/client/linux/handler/exception_handler.cc | 42 |
1 files changed, 27 insertions, 15 deletions
diff --git a/src/client/linux/handler/exception_handler.cc b/src/client/linux/handler/exception_handler.cc index 9b20fe25..5bd2d8cc 100644 --- a/src/client/linux/handler/exception_handler.cc +++ b/src/client/linux/handler/exception_handler.cc @@ -212,6 +212,12 @@ void InstallDefaultHandler(int sig) { std::vector<ExceptionHandler*>* g_handler_stack_ = NULL; pthread_mutex_t g_handler_stack_mutex_ = PTHREAD_MUTEX_INITIALIZER; +// sizeof(CrashContext) can be too big w.r.t the size of alternatate stack +// for SignalHandler(). Keep the crash context as a .bss field. Exception +// handlers are serialized by the |g_handler_stack_mutex_| and at most one at a +// time can use |g_crash_context_|. +ExceptionHandler::CrashContext g_crash_context_; + } // namespace // Runs before crashing: normal context. @@ -239,6 +245,11 @@ ExceptionHandler::ExceptionHandler(const MinidumpDescriptor& descriptor, #endif pthread_mutex_lock(&g_handler_stack_mutex_); + + // Pre-fault the crash context struct. This is to avoid failing due to OOM + // if handling an exception when the process ran out of virtual memory. + memset(&g_crash_context_, 0, sizeof(g_crash_context_)); + if (!g_handler_stack_) g_handler_stack_ = new std::vector<ExceptionHandler*>; if (install_handler) { @@ -424,36 +435,37 @@ bool ExceptionHandler::HandleSignal(int sig, siginfo_t* info, void* uc) { if (signal_trusted || (signal_pid_trusted && info->si_pid == getpid())) { sys_prctl(PR_SET_DUMPABLE, 1, 0, 0, 0); } - CrashContext context; + // Fill in all the holes in the struct to make Valgrind happy. - memset(&context, 0, sizeof(context)); - memcpy(&context.siginfo, info, sizeof(siginfo_t)); - memcpy(&context.context, uc, sizeof(struct ucontext)); + memset(&g_crash_context_, 0, sizeof(g_crash_context_)); + memcpy(&g_crash_context_.siginfo, info, sizeof(siginfo_t)); + memcpy(&g_crash_context_.context, uc, sizeof(struct ucontext)); #if defined(__aarch64__) - struct ucontext *uc_ptr = (struct ucontext*)uc; - struct fpsimd_context *fp_ptr = + struct ucontext* uc_ptr = (struct ucontext*)uc; + struct fpsimd_context* fp_ptr = (struct fpsimd_context*)&uc_ptr->uc_mcontext.__reserved; if (fp_ptr->head.magic == FPSIMD_MAGIC) { - memcpy(&context.float_state, fp_ptr, sizeof(context.float_state)); + memcpy(&g_crash_context_.float_state, fp_ptr, + sizeof(g_crash_context_.float_state)); } -#elif !defined(__ARM_EABI__) && !defined(__mips__) +#elif !defined(__ARM_EABI__) && !defined(__mips__) // FP state is not part of user ABI on ARM Linux. // In case of MIPS Linux FP state is already part of struct ucontext // and 'float_state' is not a member of CrashContext. - struct ucontext *uc_ptr = (struct ucontext*)uc; + struct ucontext* uc_ptr = (struct ucontext*)uc; if (uc_ptr->uc_mcontext.fpregs) { - memcpy(&context.float_state, - uc_ptr->uc_mcontext.fpregs, - sizeof(context.float_state)); + memcpy(&g_crash_context_.float_state, uc_ptr->uc_mcontext.fpregs, + sizeof(g_crash_context_.float_state)); } #endif - context.tid = syscall(__NR_gettid); + g_crash_context_.tid = syscall(__NR_gettid); if (crash_handler_ != NULL) { - if (crash_handler_(&context, sizeof(context), callback_context_)) { + if (crash_handler_(&g_crash_context_, sizeof(g_crash_context_), + callback_context_)) { return true; } } - return GenerateDump(&context); + return GenerateDump(&g_crash_context_); } // This is a public interface to HandleSignal that allows the client to |