fix: share thread signal stacks with macOS

This commit is contained in:
nmzik
2026-09-07 12:17:30 +04:00
parent 27ee6f02d6
commit b61360a0c0
+51 -45
View File
@@ -5,16 +5,17 @@
#if KYTY_PLATFORM == KYTY_PLATFORM_WINDOWS
#include <windows.h> // IWYU pragma: keep
#elif defined(__APPLE__)
#include <csignal>
#include <sys/ucontext.h>
#else
#include <algorithm>
#include <csignal>
#include <cstdlib>
#include <initializer_list>
#include <ucontext.h> // IWYU pragma: keep
#include <unistd.h>
#if defined(__APPLE__)
#include <sys/ucontext.h>
#else
#include <ucontext.h> // IWYU pragma: keep
#endif
#endif
// IWYU pragma: no_include <errhandlingapi.h>
@@ -34,6 +35,51 @@ static_assert(decltype(g_handler)::is_always_lock_free);
static_assert(decltype(g_install_state)::is_always_lock_free);
#endif
#if KYTY_PLATFORM == KYTY_PLATFORM_LINUX
// macOS uses the same POSIX platform setting and needs a signal stack too.
class ThreadSignalStack {
public:
ThreadSignalStack() {
const auto page_size = static_cast<size_t>(::getpagesize());
const auto stack_size =
(std::max<size_t>(64 * 1024, MINSIGSTKSZ) + page_size - 1) & ~(page_size - 1);
if (::posix_memalign(&m_memory, page_size, stack_size) != 0) {
return;
}
stack_t stack {};
stack.ss_sp = m_memory;
stack.ss_size = stack_size;
if (::sigaltstack(&stack, &m_previous) != 0) {
std::free(m_memory);
m_memory = nullptr;
}
}
~ThreadSignalStack() {
if (m_memory != nullptr && ::sigaltstack(&m_previous, nullptr) == 0) {
std::free(m_memory);
}
}
[[nodiscard]] bool IsInitialized() const { return m_memory != nullptr; }
KYTY_CLASS_NO_COPY(ThreadSignalStack)
private:
void* m_memory = nullptr;
stack_t m_previous {};
};
bool InitializeThreadSignalStack() {
// Keep fault handling off guest stacks, which GPU tracking can make read-only.
thread_local ThreadSignalStack signal_stack;
return signal_stack.IsInitialized();
}
#endif
#if KYTY_PLATFORM == KYTY_PLATFORM_WINDOWS
static LONG WINAPI ExceptionFilter(PEXCEPTION_POINTERS exception) noexcept {
@@ -166,46 +212,6 @@ static void SignalHandler(int sig, siginfo_t* si, void* uctx) {
#else
class ThreadSignalStack {
public:
ThreadSignalStack() {
const auto page_size = static_cast<size_t>(::getpagesize());
const auto stack_size =
(std::max<size_t>(64 * 1024, MINSIGSTKSZ) + page_size - 1) & ~(page_size - 1);
if (::posix_memalign(&m_memory, page_size, stack_size) != 0) {
return;
}
stack_t stack {};
stack.ss_sp = m_memory;
stack.ss_size = stack_size;
if (::sigaltstack(&stack, &m_previous) != 0) {
std::free(m_memory);
m_memory = nullptr;
}
}
~ThreadSignalStack() {
if (m_memory != nullptr && ::sigaltstack(&m_previous, nullptr) == 0) {
std::free(m_memory);
}
}
[[nodiscard]] bool IsInitialized() const { return m_memory != nullptr; }
KYTY_CLASS_NO_COPY(ThreadSignalStack)
private:
void* m_memory = nullptr;
stack_t m_previous {};
};
bool InitializeThreadSignalStack() {
// Keep fault handling off guest stacks, which GPU tracking can make read-only.
thread_local ThreadSignalStack signal_stack;
return signal_stack.IsInitialized();
}
// x86-64 page-fault error bits.
constexpr uint64_t PAGE_FAULT_ERROR_WRITE = 0x02;
constexpr uint64_t PAGE_FAULT_ERROR_INSTRUCTION = 0x10;
@@ -295,7 +301,7 @@ bool InstallHandler(Handler handler) {
#elif defined(__APPLE__)
struct sigaction sa {};
sa.sa_sigaction = SignalHandler;
sa.sa_flags = SA_SIGINFO;
sa.sa_flags = SA_SIGINFO | SA_ONSTACK;
sigemptyset(&sa.sa_mask);
// The guest signal-dispatch path (KernelRaiseException) interrupts threads with
// SIGUSR1; block it while a fault is being resolved so a stop-the-world request