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Merge "Revert "Improve stack overflow diagnostics.""

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Guang Zhu 2013-07-17 03:17:19 +00:00 committed by Gerrit Code Review
commit 2cf5a6f662
3 changed files with 33 additions and 57 deletions
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8
libc/bionic/pthread_attr.cpp
View file

@ -30,16 +30,12 @@
#include "pthread_internal.h"
// Traditionally we give threads a 1MiB stack. When we started allocating per-thread
// alternate signal stacks to ease debugging of stack overflows, we subtracted the
// same amount we were using there from the default thread stack size. This should
// keep memory usage roughly constant.
#define DEFAULT_THREAD_STACK_SIZE ((1 * 1024 * 1024) - SIGSTKSZ)
#define DEFAULT_STACK_SIZE (1024 * 1024)
int pthread_attr_init(pthread_attr_t* attr) {
attr->flags = 0;
attr->stack_base = NULL;
attr->stack_size = DEFAULT_THREAD_STACK_SIZE;
attr->stack_size = DEFAULT_STACK_SIZE;
attr->guard_size = PAGE_SIZE;
attr->sched_policy = SCHED_NORMAL;
attr->sched_priority = 0;

21
libc/bionic/pthread_create.cpp
View file

@ -62,15 +62,6 @@ void __init_tls(pthread_internal_t* thread) {
thread->tls[i] = NULL;
}
// Create and set an alternate signal stack.
stack_t ss;
ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
if (ss.ss_sp != MAP_FAILED) {
ss.ss_size = SIGSTKSZ;
ss.ss_flags = 0;
sigaltstack(&ss, NULL);
}
// Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0.
thread->tls[TLS_SLOT_SELF] = thread->tls;
thread->tls[TLS_SLOT_THREAD_ID] = thread;
@ -80,9 +71,7 @@ void __init_tls(pthread_internal_t* thread) {
__set_tls(thread->tls);
}
// This trampoline is called from the assembly _pthread_clone function.
// Our 'tls' and __pthread_clone's 'child_stack' are one and the same, just growing in
// opposite directions.
// This trampoline is called from the assembly _pthread_clone() function.
extern "C" void __thread_entry(void* (*func)(void*), void* arg, void** tls) {
// Wait for our creating thread to release us. This lets it have time to
// notify gdb about this thread before we start doing anything.
@ -198,12 +187,8 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
thread->attr.flags |= PTHREAD_ATTR_FLAG_USER_STACK;
}
// Make room for the TLS area.
// The child stack is the same address, just growing in the opposite direction.
// At offsets >= 0, we have the TLS slots.
// At offsets < 0, we have the child stack.
// Make room for TLS.
void** tls = (void**)((uint8_t*)(thread->attr.stack_base) + thread->attr.stack_size - BIONIC_TLS_SLOTS * sizeof(void*));
void* child_stack = tls;
// Create a mutex for the thread in TLS_SLOT_SELF to wait on once it starts so we can keep
// it from doing anything until after we notify the debugger about it
@ -219,7 +204,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
int flags = CLONE_FILES | CLONE_FS | CLONE_VM | CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM;
int tid = __pthread_clone(start_routine, child_stack, flags, arg);
int tid = __pthread_clone(start_routine, tls, flags, arg);
if (tid < 0) {
int clone_errno = errno;
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_STACK) == 0) {

61
linker/debugger.cpp
View file

@ -28,15 +28,14 @@
#include "linker.h"
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>
#include <signal.h>
#include <sys/prctl.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
extern "C" int tgkill(int tgid, int tid, int sig);
@ -110,7 +109,7 @@ static int socket_abstract_client(const char* name, int type) {
* mutex is being held, so we don't want to use any libc functions that
* could allocate memory or hold a lock.
*/
static void log_signal_summary(int signum, const siginfo_t* info) {
static void logSignalSummary(int signum, const siginfo_t* info) {
const char* signal_name;
switch (signum) {
case SIGILL: signal_name = "SIGILL"; break;
@ -150,26 +149,26 @@ static void log_signal_summary(int signum, const siginfo_t* info) {
/*
* Returns true if the handler for signal "signum" has SA_SIGINFO set.
*/
static bool have_siginfo(int signum) {
struct sigaction old_action, new_action;
static bool haveSiginfo(int signum) {
struct sigaction oldact, newact;
memset(&new_action, 0, sizeof(new_action));
new_action.sa_handler = SIG_DFL;
new_action.sa_flags = SA_RESTART;
sigemptyset(&new_action.sa_mask);
memset(&newact, 0, sizeof(newact));
newact.sa_handler = SIG_DFL;
newact.sa_flags = SA_RESTART;
sigemptyset(&newact.sa_mask);
if (sigaction(signum, &new_action, &old_action) < 0) {
if (sigaction(signum, &newact, &oldact) < 0) {
__libc_format_log(ANDROID_LOG_WARN, "libc", "Failed testing for SA_SIGINFO: %s",
strerror(errno));
return false;
}
bool result = (old_action.sa_flags & SA_SIGINFO) != 0;
bool ret = (oldact.sa_flags & SA_SIGINFO) != 0;
if (sigaction(signum, &old_action, NULL) == -1) {
if (sigaction(signum, &oldact, NULL) == -1) {
__libc_format_log(ANDROID_LOG_WARN, "libc", "Restore failed in test for SA_SIGINFO: %s",
strerror(errno));
}
return result;
return ret;
}
/*
@ -181,11 +180,11 @@ void debuggerd_signal_handler(int n, siginfo_t* info, void*) {
* It's possible somebody cleared the SA_SIGINFO flag, which would mean
* our "info" arg holds an undefined value.
*/
if (!have_siginfo(n)) {
if (!haveSiginfo(n)) {
info = NULL;
}
log_signal_summary(n, info);
logSignalSummary(n, info);
pid_t tid = gettid();
int s = socket_abstract_client(DEBUGGER_SOCKET_NAME, SOCK_STREAM);
@ -246,23 +245,19 @@ void debuggerd_signal_handler(int n, siginfo_t* info, void*) {
}
void debuggerd_init() {
struct sigaction action;
memset(&action, 0, sizeof(action));
sigemptyset(&action.sa_mask);
action.sa_sigaction = debuggerd_signal_handler;
action.sa_flags = SA_RESTART | SA_SIGINFO;
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_sigaction = debuggerd_signal_handler;
act.sa_flags = SA_RESTART | SA_SIGINFO;
sigemptyset(&act.sa_mask);
// Use the alternate signal stack if available so we can catch stack overflows.
action.sa_flags |= SA_ONSTACK;
sigaction(SIGABRT, &action, NULL);
sigaction(SIGBUS, &action, NULL);
sigaction(SIGFPE, &action, NULL);
sigaction(SIGILL, &action, NULL);
sigaction(SIGPIPE, &action, NULL);
sigaction(SIGSEGV, &action, NULL);
sigaction(SIGILL, &act, NULL);
sigaction(SIGABRT, &act, NULL);
sigaction(SIGBUS, &act, NULL);
sigaction(SIGFPE, &act, NULL);
sigaction(SIGSEGV, &act, NULL);
#if defined(SIGSTKFLT)
sigaction(SIGSTKFLT, &action, NULL);
sigaction(SIGSTKFLT, &act, NULL);
#endif
sigaction(SIGTRAP, &action, NULL);
sigaction(SIGPIPE, &act, NULL);
}