bool JavaThread::pd_get_top_frame(frame* fr_addr,
void* ucontext, bool isInJava) {
assert(this->is_Java_thread(), "must be JavaThread");
JavaThread* jt = (JavaThread *)this;
// last_Java_frame is always walkable and safe use it if we have it
if (jt->has_last_Java_frame()) {
*fr_addr = jt->pd_last_frame();
return true;
}
ucontext_t* uc = (ucontext_t*) ucontext;
// We always want to use the initial frame we create from the ucontext as
// it certainly signals where we currently are. However that frame may not
// be safe for calling sender. In that case if we have a last_Java_frame
// then the forte walker will switch to that frame as the virtual sender
// for the frame we create here which is not sender safe.
intptr_t* ret_fp;
intptr_t* ret_sp;
ExtendedPC addr = os::Solaris::fetch_frame_from_ucontext(this, uc, &ret_sp, &ret_fp);
// Something would really have to be screwed up to get a NULL pc
if (addr.pc() == NULL) {
assert(false, "NULL pc from signal handler!");
return false;
}
// If sp and fp are nonsense just leave them out
if (!jt->on_local_stack((address)ret_sp)) {
ret_sp = NULL;
ret_fp = NULL;
} else {
// sp is reasonable is fp reasonable?
if ((address)ret_fp >= jt->stack_base() || ret_fp < ret_sp) {
ret_fp = NULL;
}
}
frame ret_frame(ret_sp, ret_fp, addr.pc());
*fr_addr = ret_frame;
return true;
}
extern "C" JNIEXPORT int
JVM_handle_linux_signal(int sig,
siginfo_t* info,
void* ucVoid,
int abort_if_unrecognized) {
ucontext_t* uc = (ucontext_t*) ucVoid;
Thread* t = Thread::current_or_null_safe();
SignalHandlerMark shm(t);
// handle SafeFetch faults
if (sig == SIGSEGV || sig == SIGBUS) {
sigjmp_buf* const pjb = get_jmp_buf_for_continuation();
if (pjb) {
siglongjmp(*pjb, 1);
}
}
// Note: it's not uncommon that JNI code uses signal/sigset to
// install then restore certain signal handler (e.g. to temporarily
// block SIGPIPE, or have a SIGILL handler when detecting CPU
// type). When that happens, JVM_handle_linux_signal() might be
// invoked with junk info/ucVoid. To avoid unnecessary crash when
// libjsig is not preloaded, try handle signals that do not require
// siginfo/ucontext first.
if (sig == SIGPIPE || sig == SIGXFSZ) {
// allow chained handler to go first
if (os::Linux::chained_handler(sig, info, ucVoid)) {
return true;
} else {
// Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
return true;
}
}
JavaThread* thread = NULL;
VMThread* vmthread = NULL;
if (os::Linux::signal_handlers_are_installed) {
if (t != NULL ){
if(t->is_Java_thread()) {
thread = (JavaThread*)t;
}
else if(t->is_VM_thread()){
vmthread = (VMThread *)t;
}
}
}
if (info != NULL && thread != NULL) {
// Handle ALL stack overflow variations here
if (sig == SIGSEGV) {
address addr = (address) info->si_addr;
// check if fault address is within thread stack
if (thread->on_local_stack(addr)) {
// stack overflow
if (thread->in_stack_yellow_reserved_zone(addr)) {
thread->disable_stack_yellow_reserved_zone();
ShouldNotCallThis();
}
else if (thread->in_stack_red_zone(addr)) {
thread->disable_stack_red_zone();
ShouldNotCallThis();
}
else {
// Accessing stack address below sp may cause SEGV if
// current thread has MAP_GROWSDOWN stack. This should
// only happen when current thread was created by user
// code with MAP_GROWSDOWN flag and then attached to VM.
// See notes in os_linux.cpp.
if (thread->osthread()->expanding_stack() == 0) {
thread->osthread()->set_expanding_stack();
if (os::Linux::manually_expand_stack(thread, addr)) {
thread->osthread()->clear_expanding_stack();
return true;
}
thread->osthread()->clear_expanding_stack();
}
else {
fatal("recursive segv. expanding stack.");
}
}
}
}
/*if (thread->thread_state() == _thread_in_Java) {
ShouldNotCallThis();
}
else*/ if (thread->thread_state() == _thread_in_vm &&
sig == SIGBUS && thread->doing_unsafe_access()) {
ShouldNotCallThis();
}
// jni_fast_Get<Primitive>Field can trap at certain pc's if a GC
// kicks in and the heap gets shrunk before the field access.
/*if (sig == SIGSEGV || sig == SIGBUS) {
address addr = JNI_FastGetField::find_slowcase_pc(pc);
if (addr != (address)-1) {
stub = addr;
}
}*/
// Check to see if we caught the safepoint code in the process
// of write protecting the memory serialization page. It write
// enables the page immediately after protecting it so we can
// just return to retry the write.
if (sig == SIGSEGV &&
os::is_memory_serialize_page(thread, (address) info->si_addr)) {
// Block current thread until permission is restored.
os::block_on_serialize_page_trap();
return true;
}
}
// signal-chaining
if (os::Linux::chained_handler(sig, info, ucVoid)) {
return true;
}
if (!abort_if_unrecognized) {
// caller wants another chance, so give it to him
return false;
}
#ifndef PRODUCT
if (sig == SIGSEGV) {
fatal("\n#"
"\n# /--------------------\\"
"\n# | segmentation fault |"
"\n# \\---\\ /--------------/"
"\n# /"
"\n# [-] |\\_/| "
"\n# (+)=C |o o|__ "
"\n# | | =-*-=__\\ "
"\n# OOO c_c_(___)");
}
#endif // !PRODUCT
char buf[64];
sprintf(buf, "caught unhandled signal %d", sig);
// Silence -Wformat-security warning for fatal()
PRAGMA_DIAG_PUSH
PRAGMA_FORMAT_NONLITERAL_IGNORED
fatal(buf);
PRAGMA_DIAG_POP
return true; // silence compiler warnings
}