diff options
Diffstat (limited to 'absl/debugging/internal')
| -rw-r--r-- | absl/debugging/internal/address_is_readable.cc | 133 | ||||
| -rw-r--r-- | absl/debugging/internal/demangle.cc | 12 | ||||
| -rw-r--r-- | absl/debugging/internal/elf_mem_image.cc | 27 | ||||
| -rw-r--r-- | absl/debugging/internal/elf_mem_image.h | 9 | ||||
| -rw-r--r-- | absl/debugging/internal/examine_stack.cc | 222 | ||||
| -rw-r--r-- | absl/debugging/internal/examine_stack.h | 34 | ||||
| -rw-r--r-- | absl/debugging/internal/stack_consumption.cc | 2 | ||||
| -rw-r--r-- | absl/debugging/internal/stack_consumption.h | 2 | ||||
| -rw-r--r-- | absl/debugging/internal/stacktrace_aarch64-inl.inc | 11 | ||||
| -rw-r--r-- | absl/debugging/internal/stacktrace_arm-inl.inc | 11 | ||||
| -rw-r--r-- | absl/debugging/internal/stacktrace_config.h | 18 | ||||
| -rw-r--r-- | absl/debugging/internal/stacktrace_emscripten-inl.inc | 110 | ||||
| -rw-r--r-- | absl/debugging/internal/stacktrace_powerpc-inl.inc | 11 | ||||
| -rw-r--r-- | absl/debugging/internal/stacktrace_riscv-inl.inc | 236 | ||||
| -rw-r--r-- | absl/debugging/internal/stacktrace_x86-inl.inc | 43 | ||||
| -rw-r--r-- | absl/debugging/internal/symbolize.h | 10 | ||||
| -rw-r--r-- | absl/debugging/internal/vdso_support.cc | 39 |
17 files changed, 735 insertions, 195 deletions
diff --git a/absl/debugging/internal/address_is_readable.cc b/absl/debugging/internal/address_is_readable.cc index 329c285f..4be6256b 100644 --- a/absl/debugging/internal/address_is_readable.cc +++ b/absl/debugging/internal/address_is_readable.cc @@ -30,16 +30,12 @@ bool AddressIsReadable(const void* /* addr */) { return true; } ABSL_NAMESPACE_END } // namespace absl -#else +#else // __linux__ && !__ANDROID__ -#include <fcntl.h> -#include <sys/syscall.h> +#include <stdint.h> +#include <syscall.h> #include <unistd.h> -#include <atomic> -#include <cerrno> -#include <cstdint> - #include "absl/base/internal/errno_saver.h" #include "absl/base/internal/raw_logging.h" @@ -47,93 +43,54 @@ namespace absl { ABSL_NAMESPACE_BEGIN namespace debugging_internal { -// Pack a pid and two file descriptors into a 64-bit word, -// using 16, 24, and 24 bits for each respectively. -static uint64_t Pack(uint64_t pid, uint64_t read_fd, uint64_t write_fd) { - ABSL_RAW_CHECK((read_fd >> 24) == 0 && (write_fd >> 24) == 0, - "fd out of range"); - return (pid << 48) | ((read_fd & 0xffffff) << 24) | (write_fd & 0xffffff); -} - -// Unpack x into a pid and two file descriptors, where x was created with -// Pack(). -static void Unpack(uint64_t x, int *pid, int *read_fd, int *write_fd) { - *pid = x >> 48; - *read_fd = (x >> 24) & 0xffffff; - *write_fd = x & 0xffffff; -} +// NOTE: be extra careful about adding any interposable function calls here +// (such as open(), read(), etc.). These symbols may be interposed and will get +// invoked in contexts they don't expect. +// +// NOTE: any new system calls here may also require sandbox reconfiguration. +// +bool AddressIsReadable(const void *addr) { + // Align address on 8-byte boundary. On aarch64, checking last + // byte before inaccessible page returned unexpected EFAULT. + const uintptr_t u_addr = reinterpret_cast<uintptr_t>(addr) & ~7; + addr = reinterpret_cast<const void *>(u_addr); -// Return whether the byte at *addr is readable, without faulting. -// Save and restores errno. Returns true on systems where -// unimplemented. -// This is a namespace-scoped variable for correct zero-initialization. -static std::atomic<uint64_t> pid_and_fds; // initially 0, an invalid pid. + // rt_sigprocmask below will succeed for this input. + if (addr == nullptr) return false; -bool AddressIsReadable(const void *addr) { absl::base_internal::ErrnoSaver errno_saver; - // We test whether a byte is readable by using write(). Normally, this would - // be done via a cached file descriptor to /dev/null, but linux fails to - // check whether the byte is readable when the destination is /dev/null, so - // we use a cached pipe. We store the pid of the process that created the - // pipe to handle the case where a process forks, and the child closes all - // the file descriptors and then calls this routine. This is not perfect: - // the child could use the routine, then close all file descriptors and then - // use this routine again. But the likely use of this routine is when - // crashing, to test the validity of pages when dumping the stack. Beware - // that we may leak file descriptors, but we're unlikely to leak many. - int bytes_written; - int current_pid = getpid() & 0xffff; // we use only the low order 16 bits - do { // until we do not get EBADF trying to use file descriptors - int pid; - int read_fd; - int write_fd; - uint64_t local_pid_and_fds = pid_and_fds.load(std::memory_order_acquire); - Unpack(local_pid_and_fds, &pid, &read_fd, &write_fd); - while (current_pid != pid) { - int p[2]; - // new pipe - if (pipe(p) != 0) { - ABSL_RAW_LOG(FATAL, "Failed to create pipe, errno=%d", errno); - } - fcntl(p[0], F_SETFD, FD_CLOEXEC); - fcntl(p[1], F_SETFD, FD_CLOEXEC); - uint64_t new_pid_and_fds = Pack(current_pid, p[0], p[1]); - if (pid_and_fds.compare_exchange_strong( - local_pid_and_fds, new_pid_and_fds, std::memory_order_release, - std::memory_order_relaxed)) { - local_pid_and_fds = new_pid_and_fds; // fds exposed to other threads - } else { // fds not exposed to other threads; we can close them. - close(p[0]); - close(p[1]); - local_pid_and_fds = pid_and_fds.load(std::memory_order_acquire); - } - Unpack(local_pid_and_fds, &pid, &read_fd, &write_fd); - } - errno = 0; - // Use syscall(SYS_write, ...) instead of write() to prevent ASAN - // and other checkers from complaining about accesses to arbitrary - // memory. - do { - bytes_written = syscall(SYS_write, write_fd, addr, 1); - } while (bytes_written == -1 && errno == EINTR); - if (bytes_written == 1) { // remove the byte from the pipe - char c; - while (read(read_fd, &c, 1) == -1 && errno == EINTR) { - } - } - if (errno == EBADF) { // Descriptors invalid. - // If pid_and_fds contains the problematic file descriptors we just used, - // this call will forget them, and the loop will try again. - pid_and_fds.compare_exchange_strong(local_pid_and_fds, 0, - std::memory_order_release, - std::memory_order_relaxed); - } - } while (errno == EBADF); - return bytes_written == 1; + + // Here we probe with some syscall which + // - accepts an 8-byte region of user memory as input + // - tests for EFAULT before other validation + // - has no problematic side-effects + // + // rt_sigprocmask(2) works for this. It copies sizeof(kernel_sigset_t)==8 + // bytes from the address into the kernel memory before any validation. + // + // The call can never succeed, since the `how` parameter is not one of + // SIG_BLOCK, SIG_UNBLOCK, SIG_SETMASK. + // + // This strategy depends on Linux implementation details, + // so we rely on the test to alert us if it stops working. + // + // Some discarded past approaches: + // - msync() doesn't reject PROT_NONE regions + // - write() on /dev/null doesn't return EFAULT + // - write() on a pipe requires creating it and draining the writes + // - connect() works but is problematic for sandboxes and needs a valid + // file descriptor + // + // This can never succeed (invalid first argument to sigprocmask). + ABSL_RAW_CHECK(syscall(SYS_rt_sigprocmask, ~0, addr, nullptr, + /*sizeof(kernel_sigset_t)*/ 8) == -1, + "unexpected success"); + ABSL_RAW_CHECK(errno == EFAULT || errno == EINVAL, "unexpected errno"); + return errno != EFAULT; } } // namespace debugging_internal ABSL_NAMESPACE_END } // namespace absl -#endif +#endif // __linux__ && !__ANDROID__ diff --git a/absl/debugging/internal/demangle.cc b/absl/debugging/internal/demangle.cc index 5cd56320..93ae3279 100644 --- a/absl/debugging/internal/demangle.cc +++ b/absl/debugging/internal/demangle.cc @@ -1617,6 +1617,7 @@ static bool ParseUnresolvedName(State *state) { // ::= <2-ary operator-name> <expression> <expression> // ::= <3-ary operator-name> <expression> <expression> <expression> // ::= cl <expression>+ E +// ::= cp <simple-id> <expression>* E # Clang-specific. // ::= cv <type> <expression> # type (expression) // ::= cv <type> _ <expression>* E # type (expr-list) // ::= st <type> @@ -1639,14 +1640,23 @@ static bool ParseExpression(State *state) { return true; } - // Object/function call expression. ParseState copy = state->parse_state; + + // Object/function call expression. if (ParseTwoCharToken(state, "cl") && OneOrMore(ParseExpression, state) && ParseOneCharToken(state, 'E')) { return true; } state->parse_state = copy; + // Clang-specific "cp <simple-id> <expression>* E" + // https://clang.llvm.org/doxygen/ItaniumMangle_8cpp_source.html#l04338 + if (ParseTwoCharToken(state, "cp") && ParseSimpleId(state) && + ZeroOrMore(ParseExpression, state) && ParseOneCharToken(state, 'E')) { + return true; + } + state->parse_state = copy; + // Function-param expression (level 0). if (ParseTwoCharToken(state, "fp") && Optional(ParseCVQualifiers(state)) && Optional(ParseNumber(state, nullptr)) && ParseOneCharToken(state, '_')) { diff --git a/absl/debugging/internal/elf_mem_image.cc b/absl/debugging/internal/elf_mem_image.cc index 24cc0130..a9d66714 100644 --- a/absl/debugging/internal/elf_mem_image.cc +++ b/absl/debugging/internal/elf_mem_image.cc @@ -22,6 +22,7 @@ #include <string.h> #include <cassert> #include <cstddef> +#include "absl/base/config.h" #include "absl/base/internal/raw_logging.h" // From binutils/include/elf/common.h (this doesn't appear to be documented @@ -43,11 +44,11 @@ namespace debugging_internal { namespace { -#if __WORDSIZE == 32 +#if __SIZEOF_POINTER__ == 4 const int kElfClass = ELFCLASS32; int ElfBind(const ElfW(Sym) *symbol) { return ELF32_ST_BIND(symbol->st_info); } int ElfType(const ElfW(Sym) *symbol) { return ELF32_ST_TYPE(symbol->st_info); } -#elif __WORDSIZE == 64 +#elif __SIZEOF_POINTER__ == 8 const int kElfClass = ELFCLASS64; int ElfBind(const ElfW(Sym) *symbol) { return ELF64_ST_BIND(symbol->st_info); } int ElfType(const ElfW(Sym) *symbol) { return ELF64_ST_TYPE(symbol->st_info); } @@ -175,17 +176,17 @@ void ElfMemImage::Init(const void *base) { } switch (base_as_char[EI_DATA]) { case ELFDATA2LSB: { - if (__LITTLE_ENDIAN != __BYTE_ORDER) { - assert(false); - return; - } +#ifndef ABSL_IS_LITTLE_ENDIAN + assert(false); + return; +#endif break; } case ELFDATA2MSB: { - if (__BIG_ENDIAN != __BYTE_ORDER) { - assert(false); - return; - } +#ifndef ABSL_IS_BIG_ENDIAN + assert(false); + return; +#endif break; } default: { @@ -221,7 +222,7 @@ void ElfMemImage::Init(const void *base) { reinterpret_cast<ElfW(Dyn) *>(dynamic_program_header->p_vaddr + relocation); for (; dynamic_entry->d_tag != DT_NULL; ++dynamic_entry) { - const ElfW(Xword) value = dynamic_entry->d_un.d_val + relocation; + const auto value = dynamic_entry->d_un.d_val + relocation; switch (dynamic_entry->d_tag) { case DT_HASH: hash_ = reinterpret_cast<ElfW(Word) *>(value); @@ -350,7 +351,11 @@ void ElfMemImage::SymbolIterator::Update(int increment) { const ElfW(Versym) *version_symbol = image->GetVersym(index_); ABSL_RAW_CHECK(symbol && version_symbol, ""); const char *const symbol_name = image->GetDynstr(symbol->st_name); +#if defined(__NetBSD__) + const int version_index = version_symbol->vs_vers & VERSYM_VERSION; +#else const ElfW(Versym) version_index = version_symbol[0] & VERSYM_VERSION; +#endif const ElfW(Verdef) *version_definition = nullptr; const char *version_name = ""; if (symbol->st_shndx == SHN_UNDEF) { diff --git a/absl/debugging/internal/elf_mem_image.h b/absl/debugging/internal/elf_mem_image.h index 46bfade3..113071a9 100644 --- a/absl/debugging/internal/elf_mem_image.h +++ b/absl/debugging/internal/elf_mem_image.h @@ -31,8 +31,9 @@ #error ABSL_HAVE_ELF_MEM_IMAGE cannot be directly set #endif -#if defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) && \ - !defined(__asmjs__) && !defined(__wasm__) +#if defined(__ELF__) && !defined(__OpenBSD__) && !defined(__QNX__) && \ + !defined(__native_client__) && !defined(__asmjs__) && \ + !defined(__wasm__) && !defined(__HAIKU__) #define ABSL_HAVE_ELF_MEM_IMAGE 1 #endif @@ -40,6 +41,10 @@ #include <link.h> // for ElfW +#if defined(__FreeBSD__) && !defined(ElfW) +#define ElfW(x) __ElfN(x) +#endif + namespace absl { ABSL_NAMESPACE_BEGIN namespace debugging_internal { diff --git a/absl/debugging/internal/examine_stack.cc b/absl/debugging/internal/examine_stack.cc index 589a3ef3..5bdd341e 100644 --- a/absl/debugging/internal/examine_stack.cc +++ b/absl/debugging/internal/examine_stack.cc @@ -20,7 +20,13 @@ #include <unistd.h> #endif -#ifdef __APPLE__ +#include "absl/base/config.h" + +#ifdef ABSL_HAVE_MMAP +#include <sys/mman.h> +#endif + +#if defined(__linux__) || defined(__APPLE__) #include <sys/ucontext.h> #endif @@ -37,10 +43,115 @@ namespace absl { ABSL_NAMESPACE_BEGIN namespace debugging_internal { +namespace { +constexpr int kDefaultDumpStackFramesLimit = 64; +// The %p field width for printf() functions is two characters per byte, +// and two extra for the leading "0x". +constexpr int kPrintfPointerFieldWidth = 2 + 2 * sizeof(void*); + +ABSL_CONST_INIT SymbolizeUrlEmitter debug_stack_trace_hook = nullptr; + +// Async-signal safe mmap allocator. +void* Allocate(size_t num_bytes) { +#ifdef ABSL_HAVE_MMAP + void* p = ::mmap(nullptr, num_bytes, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + return p == MAP_FAILED ? nullptr : p; +#else + (void)num_bytes; + return nullptr; +#endif // ABSL_HAVE_MMAP +} + +void Deallocate(void* p, size_t size) { +#ifdef ABSL_HAVE_MMAP + ::munmap(p, size); +#else + (void)p; + (void)size; +#endif // ABSL_HAVE_MMAP +} + +// Print a program counter only. +void DumpPC(OutputWriter* writer, void* writer_arg, void* const pc, + const char* const prefix) { + char buf[100]; + snprintf(buf, sizeof(buf), "%s@ %*p\n", prefix, kPrintfPointerFieldWidth, pc); + writer(buf, writer_arg); +} + +// Print a program counter and the corresponding stack frame size. +void DumpPCAndFrameSize(OutputWriter* writer, void* writer_arg, void* const pc, + int framesize, const char* const prefix) { + char buf[100]; + if (framesize <= 0) { + snprintf(buf, sizeof(buf), "%s@ %*p (unknown)\n", prefix, + kPrintfPointerFieldWidth, pc); + } else { + snprintf(buf, sizeof(buf), "%s@ %*p %9d\n", prefix, + kPrintfPointerFieldWidth, pc, framesize); + } + writer(buf, writer_arg); +} + +// Print a program counter and the corresponding symbol. +void DumpPCAndSymbol(OutputWriter* writer, void* writer_arg, void* const pc, + const char* const prefix) { + char tmp[1024]; + const char* symbol = "(unknown)"; + // Symbolizes the previous address of pc because pc may be in the + // next function. The overrun happens when the function ends with + // a call to a function annotated noreturn (e.g. CHECK). + // If symbolization of pc-1 fails, also try pc on the off-chance + // that we crashed on the first instruction of a function (that + // actually happens very often for e.g. __restore_rt). + const uintptr_t prev_pc = reinterpret_cast<uintptr_t>(pc) - 1; + if (absl::Symbolize(reinterpret_cast<const char*>(prev_pc), tmp, + sizeof(tmp)) || + absl::Symbolize(pc, tmp, sizeof(tmp))) { + symbol = tmp; + } + char buf[1024]; + snprintf(buf, sizeof(buf), "%s@ %*p %s\n", prefix, kPrintfPointerFieldWidth, + pc, symbol); + writer(buf, writer_arg); +} + +// Print a program counter, its stack frame size, and its symbol name. +// Note that there is a separate symbolize_pc argument. Return addresses may be +// at the end of the function, and this allows the caller to back up from pc if +// appropriate. +void DumpPCAndFrameSizeAndSymbol(OutputWriter* writer, void* writer_arg, + void* const pc, void* const symbolize_pc, + int framesize, const char* const prefix) { + char tmp[1024]; + const char* symbol = "(unknown)"; + if (absl::Symbolize(symbolize_pc, tmp, sizeof(tmp))) { + symbol = tmp; + } + char buf[1024]; + if (framesize <= 0) { + snprintf(buf, sizeof(buf), "%s@ %*p (unknown) %s\n", prefix, + kPrintfPointerFieldWidth, pc, symbol); + } else { + snprintf(buf, sizeof(buf), "%s@ %*p %9d %s\n", prefix, + kPrintfPointerFieldWidth, pc, framesize, symbol); + } + writer(buf, writer_arg); +} + +} // namespace + +void RegisterDebugStackTraceHook(SymbolizeUrlEmitter hook) { + debug_stack_trace_hook = hook; +} + +SymbolizeUrlEmitter GetDebugStackTraceHook() { return debug_stack_trace_hook; } + // Returns the program counter from signal context, nullptr if // unknown. vuc is a ucontext_t*. We use void* to avoid the use of // ucontext_t on non-POSIX systems. -void* GetProgramCounter(void* vuc) { +void* GetProgramCounter(void* const vuc) { #ifdef __linux__ if (vuc != nullptr) { ucontext_t* context = reinterpret_cast<ucontext_t*>(vuc); @@ -82,6 +193,8 @@ void* GetProgramCounter(void* vuc) { return reinterpret_cast<void*>(context->uc_mcontext.gregs[16]); #elif defined(__e2k__) return reinterpret_cast<void*>(context->uc_mcontext.cr0_hi); +#elif defined(__loongarch__) + return reinterpret_cast<void*>(context->uc_mcontext.__pc); #else #error "Undefined Architecture." #endif @@ -120,59 +233,17 @@ void* GetProgramCounter(void* vuc) { return nullptr; } -// The %p field width for printf() functions is two characters per byte, -// and two extra for the leading "0x". -static constexpr int kPrintfPointerFieldWidth = 2 + 2 * sizeof(void*); - -// Print a program counter, its stack frame size, and its symbol name. -// Note that there is a separate symbolize_pc argument. Return addresses may be -// at the end of the function, and this allows the caller to back up from pc if -// appropriate. -static void DumpPCAndFrameSizeAndSymbol(void (*writerfn)(const char*, void*), - void* writerfn_arg, void* pc, - void* symbolize_pc, int framesize, - const char* const prefix) { - char tmp[1024]; - const char* symbol = "(unknown)"; - if (absl::Symbolize(symbolize_pc, tmp, sizeof(tmp))) { - symbol = tmp; - } - char buf[1024]; - if (framesize <= 0) { - snprintf(buf, sizeof(buf), "%s@ %*p (unknown) %s\n", prefix, - kPrintfPointerFieldWidth, pc, symbol); - } else { - snprintf(buf, sizeof(buf), "%s@ %*p %9d %s\n", prefix, - kPrintfPointerFieldWidth, pc, framesize, symbol); - } - writerfn(buf, writerfn_arg); -} - -// Print a program counter and the corresponding stack frame size. -static void DumpPCAndFrameSize(void (*writerfn)(const char*, void*), - void* writerfn_arg, void* pc, int framesize, - const char* const prefix) { - char buf[100]; - if (framesize <= 0) { - snprintf(buf, sizeof(buf), "%s@ %*p (unknown)\n", prefix, - kPrintfPointerFieldWidth, pc); - } else { - snprintf(buf, sizeof(buf), "%s@ %*p %9d\n", prefix, - kPrintfPointerFieldWidth, pc, framesize); - } - writerfn(buf, writerfn_arg); -} - -void DumpPCAndFrameSizesAndStackTrace( - void* pc, void* const stack[], int frame_sizes[], int depth, - int min_dropped_frames, bool symbolize_stacktrace, - void (*writerfn)(const char*, void*), void* writerfn_arg) { +void DumpPCAndFrameSizesAndStackTrace(void* const pc, void* const stack[], + int frame_sizes[], int depth, + int min_dropped_frames, + bool symbolize_stacktrace, + OutputWriter* writer, void* writer_arg) { if (pc != nullptr) { // We don't know the stack frame size for PC, use 0. if (symbolize_stacktrace) { - DumpPCAndFrameSizeAndSymbol(writerfn, writerfn_arg, pc, pc, 0, "PC: "); + DumpPCAndFrameSizeAndSymbol(writer, writer_arg, pc, pc, 0, "PC: "); } else { - DumpPCAndFrameSize(writerfn, writerfn_arg, pc, 0, "PC: "); + DumpPCAndFrameSize(writer, writer_arg, pc, 0, "PC: "); } } for (int i = 0; i < depth; i++) { @@ -182,20 +253,61 @@ void DumpPCAndFrameSizesAndStackTrace( // call to a function annotated noreturn (e.g. CHECK). Note that we don't // do this for pc above, as the adjustment is only correct for return // addresses. - DumpPCAndFrameSizeAndSymbol(writerfn, writerfn_arg, stack[i], + DumpPCAndFrameSizeAndSymbol(writer, writer_arg, stack[i], reinterpret_cast<char*>(stack[i]) - 1, frame_sizes[i], " "); } else { - DumpPCAndFrameSize(writerfn, writerfn_arg, stack[i], frame_sizes[i], - " "); + DumpPCAndFrameSize(writer, writer_arg, stack[i], frame_sizes[i], " "); } } if (min_dropped_frames > 0) { char buf[100]; snprintf(buf, sizeof(buf), " @ ... and at least %d more frames\n", min_dropped_frames); - writerfn(buf, writerfn_arg); + writer(buf, writer_arg); + } +} + +// Dump current stack trace as directed by writer. +// Make sure this function is not inlined to avoid skipping too many top frames. +ABSL_ATTRIBUTE_NOINLINE +void DumpStackTrace(int min_dropped_frames, int max_num_frames, + bool symbolize_stacktrace, OutputWriter* writer, + void* writer_arg) { + // Print stack trace + void* stack_buf[kDefaultDumpStackFramesLimit]; + void** stack = stack_buf; + int num_stack = kDefaultDumpStackFramesLimit; + int allocated_bytes = 0; + + if (num_stack >= max_num_frames) { + // User requested fewer frames than we already have space for. + num_stack = max_num_frames; + } else { + const size_t needed_bytes = max_num_frames * sizeof(stack[0]); + void* p = Allocate(needed_bytes); + if (p != nullptr) { // We got the space. + num_stack = max_num_frames; + stack = reinterpret_cast<void**>(p); + allocated_bytes = needed_bytes; + } } + + size_t depth = absl::GetStackTrace(stack, num_stack, min_dropped_frames + 1); + for (size_t i = 0; i < depth; i++) { + if (symbolize_stacktrace) { + DumpPCAndSymbol(writer, writer_arg, stack[i], " "); + } else { + DumpPC(writer, writer_arg, stack[i], " "); + } + } + + auto hook = GetDebugStackTraceHook(); + if (hook != nullptr) { + (*hook)(stack, depth, writer, writer_arg); + } + + if (allocated_bytes != 0) Deallocate(stack, allocated_bytes); } } // namespace debugging_internal diff --git a/absl/debugging/internal/examine_stack.h b/absl/debugging/internal/examine_stack.h index 39336913..190af87f 100644 --- a/absl/debugging/internal/examine_stack.h +++ b/absl/debugging/internal/examine_stack.h @@ -23,17 +23,39 @@ namespace absl { ABSL_NAMESPACE_BEGIN namespace debugging_internal { +// Type of function used for printing in stack trace dumping, etc. +// We avoid closures to keep things simple. +typedef void OutputWriter(const char*, void*); + +// RegisterDebugStackTraceHook() allows to register a single routine +// `hook` that is called each time DumpStackTrace() is called. +// `hook` may be called from a signal handler. +typedef void (*SymbolizeUrlEmitter)(void* const stack[], int depth, + OutputWriter* writer, void* writer_arg); + +// Registration of SymbolizeUrlEmitter for use inside of a signal handler. +// This is inherently unsafe and must be signal safe code. +void RegisterDebugStackTraceHook(SymbolizeUrlEmitter hook); +SymbolizeUrlEmitter GetDebugStackTraceHook(); + // Returns the program counter from signal context, or nullptr if // unknown. `vuc` is a ucontext_t*. We use void* to avoid the use of // ucontext_t on non-POSIX systems. -void* GetProgramCounter(void* vuc); +void* GetProgramCounter(void* const vuc); -// Uses `writerfn` to dump the program counter, stack trace, and stack +// Uses `writer` to dump the program counter, stack trace, and stack // frame sizes. -void DumpPCAndFrameSizesAndStackTrace( - void* pc, void* const stack[], int frame_sizes[], int depth, - int min_dropped_frames, bool symbolize_stacktrace, - void (*writerfn)(const char*, void*), void* writerfn_arg); +void DumpPCAndFrameSizesAndStackTrace(void* const pc, void* const stack[], + int frame_sizes[], int depth, + int min_dropped_frames, + bool symbolize_stacktrace, + OutputWriter* writer, void* writer_arg); + +// Dump current stack trace omitting the topmost `min_dropped_frames` stack +// frames. +void DumpStackTrace(int min_dropped_frames, int max_num_frames, + bool symbolize_stacktrace, OutputWriter* writer, + void* writer_arg); } // namespace debugging_internal ABSL_NAMESPACE_END diff --git a/absl/debugging/internal/stack_consumption.cc b/absl/debugging/internal/stack_consumption.cc index e3dd51c3..51348649 100644 --- a/absl/debugging/internal/stack_consumption.cc +++ b/absl/debugging/internal/stack_consumption.cc @@ -43,7 +43,7 @@ namespace { // unspecified. Therefore, instead we hardcode the direction of the // stack on platforms we know about. #if defined(__i386__) || defined(__x86_64__) || defined(__ppc__) || \ - defined(__aarch64__) + defined(__aarch64__) || defined(__riscv) constexpr bool kStackGrowsDown = true; #else #error Need to define kStackGrowsDown diff --git a/absl/debugging/internal/stack_consumption.h b/absl/debugging/internal/stack_consumption.h index 2b5e7151..f41b64c3 100644 --- a/absl/debugging/internal/stack_consumption.h +++ b/absl/debugging/internal/stack_consumption.h @@ -26,7 +26,7 @@ #error ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION cannot be set directly #elif !defined(__APPLE__) && !defined(_WIN32) && \ (defined(__i386__) || defined(__x86_64__) || defined(__ppc__) || \ - defined(__aarch64__)) + defined(__aarch64__) || defined(__riscv)) #define ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION 1 namespace absl { diff --git a/absl/debugging/internal/stacktrace_aarch64-inl.inc b/absl/debugging/internal/stacktrace_aarch64-inl.inc index f4859d7c..4f9db9d6 100644 --- a/absl/debugging/internal/stacktrace_aarch64-inl.inc +++ b/absl/debugging/internal/stacktrace_aarch64-inl.inc @@ -176,12 +176,17 @@ static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count, // Implementation detail: we clamp the max of frames we are willing to // count, so as not to spend too much time in the loop below. const int kMaxUnwind = 200; - int j = 0; - for (; frame_pointer != nullptr && j < kMaxUnwind; j++) { + int num_dropped_frames = 0; + for (int j = 0; frame_pointer != nullptr && j < kMaxUnwind; j++) { + if (skip_count > 0) { + skip_count--; + } else { + num_dropped_frames++; + } frame_pointer = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(frame_pointer, ucp); } - *min_dropped_frames = j; + *min_dropped_frames = num_dropped_frames; } return n; } diff --git a/absl/debugging/internal/stacktrace_arm-inl.inc b/absl/debugging/internal/stacktrace_arm-inl.inc index 2a1bf2e8..102a2a12 100644 --- a/absl/debugging/internal/stacktrace_arm-inl.inc +++ b/absl/debugging/internal/stacktrace_arm-inl.inc @@ -112,11 +112,16 @@ static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count, // Implementation detail: we clamp the max of frames we are willing to // count, so as not to spend too much time in the loop below. const int kMaxUnwind = 200; - int j = 0; - for (; sp != nullptr && j < kMaxUnwind; j++) { + int num_dropped_frames = 0; + for (int j = 0; sp != nullptr && j < kMaxUnwind; j++) { + if (skip_count > 0) { + skip_count--; + } else { + num_dropped_frames++; + } sp = NextStackFrame<!IS_STACK_FRAMES>(sp); } - *min_dropped_frames = j; + *min_dropped_frames = num_dropped_frames; } return n; } diff --git a/absl/debugging/internal/stacktrace_config.h b/absl/debugging/internal/stacktrace_config.h index cca410d4..3929b1b7 100644 --- a/absl/debugging/internal/stacktrace_config.h +++ b/absl/debugging/internal/stacktrace_config.h @@ -35,7 +35,12 @@ // Thread local support required for UnwindImpl. #define ABSL_STACKTRACE_INL_HEADER \ "absl/debugging/internal/stacktrace_generic-inl.inc" -#endif +#endif // defined(ABSL_HAVE_THREAD_LOCAL) + +// Emscripten stacktraces rely on JS. Do not use them in standalone mode. +#elif defined(__EMSCRIPTEN__) && !defined(STANDALONE_WASM) +#define ABSL_STACKTRACE_INL_HEADER \ + "absl/debugging/internal/stacktrace_emscripten-inl.inc" #elif defined(__linux__) && !defined(__ANDROID__) @@ -51,7 +56,7 @@ // Note: When using glibc this may require -funwind-tables to function properly. #define ABSL_STACKTRACE_INL_HEADER \ "absl/debugging/internal/stacktrace_generic-inl.inc" -#endif +#endif // __has_include(<execinfo.h>) #elif defined(__i386__) || defined(__x86_64__) #define ABSL_STACKTRACE_INL_HEADER \ "absl/debugging/internal/stacktrace_x86-inl.inc" @@ -61,15 +66,18 @@ #elif defined(__aarch64__) #define ABSL_STACKTRACE_INL_HEADER \ "absl/debugging/internal/stacktrace_aarch64-inl.inc" +#elif defined(__riscv) +#define ABSL_STACKTRACE_INL_HEADER \ + "absl/debugging/internal/stacktrace_riscv-inl.inc" #elif defined(__has_include) #if __has_include(<execinfo.h>) // Note: When using glibc this may require -funwind-tables to function properly. #define ABSL_STACKTRACE_INL_HEADER \ "absl/debugging/internal/stacktrace_generic-inl.inc" -#endif -#endif +#endif // __has_include(<execinfo.h>) +#endif // defined(__has_include) -#endif +#endif // defined(__linux__) && !defined(__ANDROID__) // Fallback to the empty implementation. #if !defined(ABSL_STACKTRACE_INL_HEADER) diff --git a/absl/debugging/internal/stacktrace_emscripten-inl.inc b/absl/debugging/internal/stacktrace_emscripten-inl.inc new file mode 100644 index 00000000..0f444514 --- /dev/null +++ b/absl/debugging/internal/stacktrace_emscripten-inl.inc @@ -0,0 +1,110 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// Portable implementation - just use glibc +// +// Note: The glibc implementation may cause a call to malloc. +// This can cause a deadlock in HeapProfiler. + +#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_EMSCRIPTEN_INL_H_ +#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_EMSCRIPTEN_INL_H_ + +#include <emscripten.h> + +#include <atomic> +#include <cstring> + +#include "absl/base/attributes.h" +#include "absl/debugging/stacktrace.h" + +extern "C" { +uintptr_t emscripten_stack_snapshot(); +uint32_t emscripten_stack_unwind_buffer(uintptr_t pc, void *buffer, + uint32_t depth); +} + +// Sometimes, we can try to get a stack trace from within a stack +// trace, which can cause a self-deadlock. +// Protect against such reentrant call by failing to get a stack trace. +// +// We use __thread here because the code here is extremely low level -- it is +// called while collecting stack traces from within malloc and mmap, and thus +// can not call anything which might call malloc or mmap itself. +static __thread int recursive = 0; + +// The stack trace function might be invoked very early in the program's +// execution (e.g. from the very first malloc). +// As such, we suppress usage of backtrace during this early stage of execution. +static std::atomic<bool> disable_stacktraces(true); // Disabled until healthy. +// Waiting until static initializers run seems to be late enough. +// This file is included into stacktrace.cc so this will only run once. +ABSL_ATTRIBUTE_UNUSED static int stacktraces_enabler = []() { + // Check if we can even create stacktraces. If not, bail early and leave + // disable_stacktraces set as-is. + // clang-format off + if (!EM_ASM_INT({ return (typeof wasmOffsetConverter !== 'undefined'); })) { + return 0; + } + // clang-format on + disable_stacktraces.store(false, std::memory_order_relaxed); + return 0; +}(); + +template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT> +static int UnwindImpl(void **result, int *sizes, int max_depth, int skip_count, + const void *ucp, int *min_dropped_frames) { + if (recursive || disable_stacktraces.load(std::memory_order_relaxed)) { + return 0; + } + ++recursive; + + static_cast<void>(ucp); // Unused. + constexpr int kStackLength = 64; + void *stack[kStackLength]; + + int size; + uintptr_t pc = emscripten_stack_snapshot(); + size = emscripten_stack_unwind_buffer(pc, stack, kStackLength); + + int result_count = size - skip_count; + if (result_count < 0) result_count = 0; + if (result_count > max_depth) result_count = max_depth; + for (int i = 0; i < result_count; i++) result[i] = stack[i + skip_count]; + + if (IS_STACK_FRAMES) { + // No implementation for finding out the stack frame sizes yet. + memset(sizes, 0, sizeof(*sizes) * result_count); + } + if (min_dropped_frames != nullptr) { + if (size - skip_count - max_depth > 0) { + *min_dropped_frames = size - skip_count - max_depth; + } else { + *min_dropped_frames = 0; + } + } + + --recursive; + + return result_count; +} + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace debugging_internal { +bool StackTraceWorksForTest() { return true; } +} // namespace debugging_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_DEBUGGING_INTERNAL_STACKTRACE_EMSCRIPTEN_INL_H_ diff --git a/absl/debugging/internal/stacktrace_powerpc-inl.inc b/absl/debugging/internal/stacktrace_powerpc-inl.inc index cf8c0516..085cef67 100644 --- a/absl/debugging/internal/stacktrace_powerpc-inl.inc +++ b/absl/debugging/internal/stacktrace_powerpc-inl.inc @@ -231,11 +231,16 @@ static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count, // Implementation detail: we clamp the max of frames we are willing to // count, so as not to spend too much time in the loop below. const int kMaxUnwind = 1000; - int j = 0; - for (; next_sp != nullptr && j < kMaxUnwind; j++) { + int num_dropped_frames = 0; + for (int j = 0; next_sp != nullptr && j < kMaxUnwind; j++) { + if (skip_count > 0) { + skip_count--; + } else { + num_dropped_frames++; + } next_sp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(next_sp, ucp); } - *min_dropped_frames = j; + *min_dropped_frames = num_dropped_frames; } return n; } diff --git a/absl/debugging/internal/stacktrace_riscv-inl.inc b/absl/debugging/internal/stacktrace_riscv-inl.inc new file mode 100644 index 00000000..7123b71b --- /dev/null +++ b/absl/debugging/internal/stacktrace_riscv-inl.inc @@ -0,0 +1,236 @@ +// Copyright 2021 The Abseil Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_RISCV_INL_H_ +#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_RISCV_INL_H_ + +// Generate stack trace for riscv + +#include <sys/ucontext.h> + +#include "absl/base/config.h" +#if defined(__linux__) +#include <sys/mman.h> +#include <ucontext.h> +#include <unistd.h> +#endif + +#include <atomic> +#include <cassert> +#include <cstdint> +#include <iostream> + +#include "absl/base/attributes.h" +#include "absl/debugging/internal/address_is_readable.h" +#include "absl/debugging/internal/vdso_support.h" +#include "absl/debugging/stacktrace.h" + +static const uintptr_t kUnknownFrameSize = 0; + +#if defined(__linux__) +// Returns the address of the VDSO __kernel_rt_sigreturn function, if present. +static const unsigned char *GetKernelRtSigreturnAddress() { + constexpr uintptr_t kImpossibleAddress = 0; + ABSL_CONST_INIT static std::atomic<uintptr_t> memoized(kImpossibleAddress); + uintptr_t address = memoized.load(std::memory_order_relaxed); + if (address != kImpossibleAddress) { + return reinterpret_cast<const unsigned char *>(address); + } + + address = reinterpret_cast<uintptr_t>(nullptr); + +#if ABSL_HAVE_VDSO_SUPPORT + absl::debugging_internal::VDSOSupport vdso; + if (vdso.IsPresent()) { + absl::debugging_internal::VDSOSupport::SymbolInfo symbol_info; + // Symbol versioning pulled from arch/riscv/kernel/vdso/vdso.lds at v5.10. + auto lookup = [&](int type) { + return vdso.LookupSymbol("__vdso_rt_sigreturn", "LINUX_4.15", type, + &symbol_info); + }; + if ((!lookup(STT_FUNC) && !lookup(STT_NOTYPE)) || + symbol_info.address == nullptr) { + // Unexpected: VDSO is present, yet the expected symbol is missing or + // null. + assert(false && "VDSO is present, but doesn't have expected symbol"); + } else { + if (reinterpret_cast<uintptr_t>(symbol_info.address) != + kImpossibleAddress) { + address = reinterpret_cast<uintptr_t>(symbol_info.address); + } else { + assert(false && "VDSO returned invalid address"); + } + } + } +#endif + + memoized.store(address, std::memory_order_relaxed); + return reinterpret_cast<const unsigned char *>(address); +} +#endif // __linux__ + +// Compute the size of a stack frame in [low..high). We assume that low < high. +// Return size of kUnknownFrameSize. +template <typename T> +static inline uintptr_t ComputeStackFrameSize(const T *low, const T *high) { + const char *low_char_ptr = reinterpret_cast<const char *>(low); + const char *high_char_ptr = reinterpret_cast<const char *>(high); + return low < high ? high_char_ptr - low_char_ptr : kUnknownFrameSize; +} + +// Given a pointer to a stack frame, locate and return the calling stackframe, +// or return null if no stackframe can be found. Perform sanity checks (the +// strictness of which is controlled by the boolean parameter +// "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned. +template <bool STRICT_UNWINDING, bool WITH_CONTEXT> +ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS // May read random elements from stack. +ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY // May read random elements from stack. +static void ** NextStackFrame(void **old_frame_pointer, const void *uc) { + // . + // . + // . + // +-> +----------------+ + // | | return address | + // | | previous fp | + // | | ... | + // | +----------------+ <-+ + // | | return address | | + // +---|- previous fp | | + // | ... | | + // $fp ->|----------------+ | + // | return address | | + // | previous fp -|---+ + // $sp ->| ... | + // +----------------+ + void **new_frame_pointer = reinterpret_cast<void **>(old_frame_pointer[-2]); + bool check_frame_size = true; + +#if defined(__linux__) + if (WITH_CONTEXT && uc != nullptr) { + // Check to see if next frame's return address is __kernel_rt_sigreturn. + if (old_frame_pointer[-1] == GetKernelRtSigreturnAddress()) { + const ucontext_t *ucv = static_cast<const ucontext_t *>(uc); + // old_frame_pointer is not suitable for unwinding, look at ucontext to + // discover frame pointer before signal. + // + // RISCV ELF psABI has the frame pointer at x8/fp/s0. + // -- RISCV psABI Table 18.2 + void **const pre_signal_frame_pointer = + reinterpret_cast<void **>(ucv->uc_mcontext.__gregs[8]); + + // Check the alleged frame pointer is actually readable. This is to + // prevent "double fault" in case we hit the first fault due to stack + // corruption. + if (!absl::debugging_internal::AddressIsReadable( + pre_signal_frame_pointer)) + return nullptr; + + // Alleged frame pointer is readable, use it for further unwinding. + new_frame_pointer = pre_signal_frame_pointer; + + // Skip frame size check if we return from a signal. We may be using an + // alterate stack for signals. + check_frame_size = false; + } + } +#endif + + // The RISCV ELF psABI mandates that the stack pointer is always 16-byte + // aligned. + // FIXME(abdulras) this doesn't hold for ILP32E which only mandates a 4-byte + // alignment. + if ((reinterpret_cast<uintptr_t>(new_frame_pointer) & 15) != 0) + return nullptr; + + // Check frame size. In strict mode, we assume frames to be under 100,000 + // bytes. In non-strict mode, we relax the limit to 1MB. + if (check_frame_size) { + const uintptr_t max_size = STRICT_UNWINDING ? 100000 : 1000000; + const uintptr_t frame_size = + ComputeStackFrameSize(old_frame_pointer, new_frame_pointer); + if (frame_size == kUnknownFrameSize || frame_size > max_size) + return nullptr; + } + + return new_frame_pointer; +} + +template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT> +ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS // May read random elements from stack. +ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY // May read random elements from stack. +static int UnwindImpl(void **result, int *sizes, int max_depth, int skip_count, + const void *ucp, int *min_dropped_frames) { + // The `frame_pointer` that is computed here points to the top of the frame. + // The two words preceding the address are the return address and the previous + // frame pointer. +#if defined(__GNUC__) + void **frame_pointer = reinterpret_cast<void **>(__builtin_frame_address(0)); +#else +#error reading stack pointer not yet supported on this platform +#endif + + int n = 0; + void *return_address = nullptr; + while (frame_pointer && n < max_depth) { + return_address = frame_pointer[-1]; + + // The absl::GetStackFrames routine is called when we are in some + // informational context (the failure signal handler for example). Use the + // non-strict unwinding rules to produce a stack trace that is as complete + // as possible (even if it contains a few bogus entries in some rare cases). + void **next_frame_pointer = + NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(frame_pointer, ucp); + + if (skip_count > 0) { + skip_count--; + } else { + result[n] = return_address; + if (IS_STACK_FRAMES) { + sizes[n] = ComputeStackFrameSize(frame_pointer, next_frame_pointer); + } + n++; + } + + frame_pointer = next_frame_pointer; + } + + if (min_dropped_frames != nullptr) { + // Implementation detail: we clamp the max of frames we are willing to + // count, so as not to spend too much time in the loop below. + const int kMaxUnwind = 200; + int num_dropped_frames = 0; + for (int j = 0; frame_pointer != nullptr && j < kMaxUnwind; j++) { + if (skip_count > 0) { + skip_count--; + } else { + num_dropped_frames++; + } + frame_pointer = + NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(frame_pointer, ucp); + } + *min_dropped_frames = num_dropped_frames; + } + + return n; +} + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace debugging_internal { +bool StackTraceWorksForTest() { return true; } +} // namespace debugging_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif diff --git a/absl/debugging/internal/stacktrace_x86-inl.inc b/absl/debugging/internal/stacktrace_x86-inl.inc index bc320ff7..1b5d8235 100644 --- a/absl/debugging/internal/stacktrace_x86-inl.inc +++ b/absl/debugging/internal/stacktrace_x86-inl.inc @@ -27,6 +27,7 @@ #include <cassert> #include <cstdint> +#include <limits> #include "absl/base/macros.h" #include "absl/base/port.h" @@ -132,9 +133,8 @@ static uintptr_t GetFP(const void *vuc) { const uintptr_t bp = 0; const uintptr_t sp = 0; #endif - // Sanity-check that the base pointer is valid. It should be as long as - // SHRINK_WRAP_FRAME_POINTER is not set, but it's possible that some code in - // the process is compiled with --copt=-fomit-frame-pointer or + // Sanity-check that the base pointer is valid. It's possible that some + // code in the process is compiled with --copt=-fomit-frame-pointer or // --copt=-momit-leaf-frame-pointer. // // TODO(bcmills): -momit-leaf-frame-pointer is currently the default @@ -159,7 +159,8 @@ static uintptr_t GetFP(const void *vuc) { template <bool STRICT_UNWINDING, bool WITH_CONTEXT> ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS // May read random elements from stack. ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY // May read random elements from stack. -static void **NextStackFrame(void **old_fp, const void *uc) { +static void **NextStackFrame(void **old_fp, const void *uc, + size_t stack_low, size_t stack_high) { void **new_fp = (void **)*old_fp; #if defined(__linux__) && defined(__i386__) @@ -247,7 +248,7 @@ static void **NextStackFrame(void **old_fp, const void *uc) { // using an alternate signal stack. // // TODO(bcmills): The GetFP call should be completely unnecessary when - // SHRINK_WRAP_FRAME_POINTER is set (because we should be back in the thread's + // ENABLE_COMBINED_UNWINDER is set (because we should be back in the thread's // stack by this point), but it is empirically still needed (e.g. when the // stack includes a call to abort). unw_get_reg returns UNW_EBADREG for some // frames. Figure out why GetValidFrameAddr and/or libunwind isn't doing what @@ -258,6 +259,18 @@ static void **NextStackFrame(void **old_fp, const void *uc) { // at a greater address that the current one. if (new_fp_u <= old_fp_u) return nullptr; if (new_fp_u - old_fp_u > kMaxFrameBytes) return nullptr; + + if (stack_low < old_fp_u && old_fp_u <= stack_high) { + // Old BP was in the expected stack region... + if (!(stack_low < new_fp_u && new_fp_u <= stack_high)) { + // ... but new BP is outside of expected stack region. + // It is most likely bogus. + return nullptr; + } + } else { + // We may be here if we are executing in a co-routine with a + // separate stack. We can't do safety checks in this case. + } } else { if (new_fp == nullptr) return nullptr; // skip AddressIsReadable() below // In the non-strict mode, allow discontiguous stack frames. @@ -297,13 +310,17 @@ static int UnwindImpl(void **result, int *sizes, int max_depth, int skip_count, int n = 0; void **fp = reinterpret_cast<void **>(__builtin_frame_address(0)); + size_t stack_low = getpagesize(); // Assume that the first page is not stack. + size_t stack_high = std::numeric_limits<size_t>::max() - sizeof(void *); + while (fp && n < max_depth) { if (*(fp + 1) == reinterpret_cast<void *>(0)) { // In 64-bit code, we often see a frame that // points to itself and has a return address of 0. break; } - void **next_fp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(fp, ucp); + void **next_fp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>( + fp, ucp, stack_low, stack_high); if (skip_count > 0) { skip_count--; } else { @@ -324,11 +341,17 @@ static int UnwindImpl(void **result, int *sizes, int max_depth, int skip_count, // Implementation detail: we clamp the max of frames we are willing to // count, so as not to spend too much time in the loop below. const int kMaxUnwind = 1000; - int j = 0; - for (; fp != nullptr && j < kMaxUnwind; j++) { - fp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(fp, ucp); + int num_dropped_frames = 0; + for (int j = 0; fp != nullptr && j < kMaxUnwind; j++) { + if (skip_count > 0) { + skip_count--; + } else { + num_dropped_frames++; + } + fp = NextStackFrame<!IS_STACK_FRAMES, IS_WITH_CONTEXT>(fp, ucp, stack_low, + stack_high); } - *min_dropped_frames = j; + *min_dropped_frames = num_dropped_frames; } return n; } diff --git a/absl/debugging/internal/symbolize.h b/absl/debugging/internal/symbolize.h index 4f26130f..27d5e652 100644 --- a/absl/debugging/internal/symbolize.h +++ b/absl/debugging/internal/symbolize.h @@ -28,8 +28,8 @@ #ifdef ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE #error ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE cannot be directly set -#elif defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) && \ - !defined(__asmjs__) && !defined(__wasm__) +#elif defined(__ELF__) && defined(__GLIBC__) && !defined(__native_client__) \ + && !defined(__asmjs__) && !defined(__wasm__) #define ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE 1 #include <elf.h> @@ -68,6 +68,12 @@ ABSL_NAMESPACE_END #define ABSL_INTERNAL_HAVE_DARWIN_SYMBOLIZE 1 #endif +#ifdef ABSL_INTERNAL_HAVE_EMSCRIPTEN_SYMBOLIZE +#error ABSL_INTERNAL_HAVE_EMSCRIPTEN_SYMBOLIZE cannot be directly set +#elif defined(__EMSCRIPTEN__) +#define ABSL_INTERNAL_HAVE_EMSCRIPTEN_SYMBOLIZE 1 +#endif + namespace absl { ABSL_NAMESPACE_BEGIN namespace debugging_internal { diff --git a/absl/debugging/internal/vdso_support.cc b/absl/debugging/internal/vdso_support.cc index 6be16d90..40eb055f 100644 --- a/absl/debugging/internal/vdso_support.cc +++ b/absl/debugging/internal/vdso_support.cc @@ -20,12 +20,25 @@ #ifdef ABSL_HAVE_VDSO_SUPPORT // defined in vdso_support.h +#if !defined(__has_include) +#define __has_include(header) 0 +#endif + #include <errno.h> #include <fcntl.h> +#if __has_include(<syscall.h>) +#include <syscall.h> +#elif __has_include(<sys/syscall.h>) #include <sys/syscall.h> +#endif #include <unistd.h> -#if __GLIBC_PREREQ(2, 16) // GLIBC-2.16 implements getauxval. +#if !defined(__UCLIBC__) && defined(__GLIBC__) && \ + (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 16)) +#define ABSL_HAVE_GETAUXVAL +#endif + +#ifdef ABSL_HAVE_GETAUXVAL #include <sys/auxv.h> #endif @@ -37,6 +50,17 @@ #define AT_SYSINFO_EHDR 33 // for crosstoolv10 #endif +#if defined(__NetBSD__) +using Elf32_auxv_t = Aux32Info; +using Elf64_auxv_t = Aux64Info; +#endif +#if defined(__FreeBSD__) +#if defined(__ELF_WORD_SIZE) && __ELF_WORD_SIZE == 64 +using Elf64_auxv_t = Elf64_Auxinfo; +#endif +using Elf32_auxv_t = Elf32_Auxinfo; +#endif + namespace absl { ABSL_NAMESPACE_BEGIN namespace debugging_internal { @@ -45,7 +69,9 @@ ABSL_CONST_INIT std::atomic<const void *> VDSOSupport::vdso_base_( debugging_internal::ElfMemImage::kInvalidBase); -std::atomic<VDSOSupport::GetCpuFn> VDSOSupport::getcpu_fn_(&InitAndGetCPU); +ABSL_CONST_INIT std::atomic<VDSOSupport::GetCpuFn> VDSOSupport::getcpu_fn_( + &InitAndGetCPU); + VDSOSupport::VDSOSupport() // If vdso_base_ is still set to kInvalidBase, we got here // before VDSOSupport::Init has been called. Call it now. @@ -65,7 +91,7 @@ VDSOSupport::VDSOSupport() // the operation should be idempotent. const void *VDSOSupport::Init() { const auto kInvalidBase = debugging_internal::ElfMemImage::kInvalidBase; -#if __GLIBC_PREREQ(2, 16) +#ifdef ABSL_HAVE_GETAUXVAL if (vdso_base_.load(std::memory_order_relaxed) == kInvalidBase) { errno = 0; const void *const sysinfo_ehdr = @@ -74,7 +100,7 @@ const void *VDSOSupport::Init() { vdso_base_.store(sysinfo_ehdr, std::memory_order_relaxed); } } -#endif // __GLIBC_PREREQ(2, 16) +#endif // ABSL_HAVE_GETAUXVAL if (vdso_base_.load(std::memory_order_relaxed) == kInvalidBase) { int fd = open("/proc/self/auxv", O_RDONLY); if (fd == -1) { @@ -86,8 +112,13 @@ const void *VDSOSupport::Init() { ElfW(auxv_t) aux; while (read(fd, &aux, sizeof(aux)) == sizeof(aux)) { if (aux.a_type == AT_SYSINFO_EHDR) { +#if defined(__NetBSD__) + vdso_base_.store(reinterpret_cast<void *>(aux.a_v), + std::memory_order_relaxed); +#else vdso_base_.store(reinterpret_cast<void *>(aux.a_un.a_val), std::memory_order_relaxed); +#endif break; } } |