#893: Fix [no_Java_frame] on ARM64

src/stackFrame.h

@@ -66,6 +66,7 @@ class StackFrame {
 
     bool unwindStub(instruction_t* entry, const char* name, uintptr_t& pc, uintptr_t& sp, uintptr_t& fp);
     bool unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintptr_t& fp);
+    bool unwindAtomicStub(const void*& pc);
 
     void adjustSP(const void* entry, const void* pc, uintptr_t& sp);
 

src/stackFrame_aarch64.cpp

@@ -151,6 +151,19 @@ bool StackFrame::unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintp
     return true;
 }
 
+bool StackFrame::unwindAtomicStub(const void*& pc) {
+    // VM threads may call generated atomic stubs, which are not normally walkable
+    const void* lr = (const void*)link();
+    if (VMStructs::libjvm()->contains(lr)) {
+        NMethod* nm = CodeHeap::findNMethod(pc);
+        if (nm != NULL && strncmp(nm->name(), "Stub", 4) == 0) {
+            pc = lr;
+            return true;
+        }
+    }
+    return false;
+}
+
 void StackFrame::adjustSP(const void* entry, const void* pc, uintptr_t& sp) {
     instruction_t* ip = (instruction_t*)pc;
     if (ip > entry && (ip[-1] == 0xa9bf27ff || (ip[-1] == 0xd63f0100 && ip[-2] == 0xa9bf27ff))) {

src/stackFrame_arm.cpp

@@ -101,6 +101,11 @@ bool StackFrame::unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintp
     return true;
 }
 
+bool StackFrame::unwindAtomicStub(const void*& pc) {
+    // Not needed
+    return false;
+}
+
 void StackFrame::adjustSP(const void* entry, const void* pc, uintptr_t& sp) {
     // Not needed
 }

src/stackFrame_i386.cpp

@@ -116,6 +116,11 @@ bool StackFrame::unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintp
     return false;
 }
 
+bool StackFrame::unwindAtomicStub(const void*& pc) {
+    // Not needed
+    return false;
+}
+
 void StackFrame::adjustSP(const void* entry, const void* pc, uintptr_t& sp) {
     // Not needed
 }

src/stackFrame_loongarch64.cpp

@@ -82,6 +82,11 @@ bool StackFrame::unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintp
     return false;
 }
 
+bool StackFrame::unwindAtomicStub(const void*& pc) {
+    // Not needed
+    return false;
+}
+
 void StackFrame::adjustSP(const void* entry, const void* pc, uintptr_t& sp) {
     // Not yet implemented
 }

src/stackFrame_ppc64.cpp

@@ -127,6 +127,11 @@ bool StackFrame::unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintp
     return true;
 }
 
+bool StackFrame::unwindAtomicStub(const void*& pc) {
+    // Not needed
+    return false;
+}
+
 void StackFrame::adjustSP(const void* entry, const void* pc, uintptr_t& sp) {
     // Not needed
 }

src/stackFrame_riscv64.cpp

@@ -82,6 +82,11 @@ bool StackFrame::unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintp
     return false;
 }
 
+bool StackFrame::unwindAtomicStub(const void*& pc) {
+    // Not needed
+    return false;
+}
+
 void StackFrame::adjustSP(const void* entry, const void* pc, uintptr_t& sp) {
     // Not yet implemented
 }

src/stackFrame_x64.cpp

@@ -144,6 +144,11 @@ bool StackFrame::unwindCompiled(NMethod* nm, uintptr_t& pc, uintptr_t& sp, uintp
     return false;
 }
 
+bool StackFrame::unwindAtomicStub(const void*& pc) {
+    // Not needed
+    return false;
+}
+
 void StackFrame::adjustSP(const void* entry, const void* pc, uintptr_t& sp) {
     // Not needed
 }

src/stackWalker.cpp

@@ -58,12 +58,12 @@ int StackWalker::walkFP(void* ucontext, const void** callchain, int max_depth, S
     uintptr_t sp;
     uintptr_t bottom = (uintptr_t)&sp + MAX_WALK_SIZE;
 
+    StackFrame frame(ucontext);
     if (ucontext == NULL) {
         pc = __builtin_return_address(0);
         fp = (uintptr_t)__builtin_frame_address(1);
         sp = (uintptr_t)__builtin_frame_address(0);
     } else {
-        StackFrame frame(ucontext);
         pc = (const void*)frame.pc();
         fp = frame.fp();
         sp = frame.sp();
@@ -73,7 +73,7 @@ int StackWalker::walkFP(void* ucontext, const void** callchain, int max_depth, S
 
     // Walk until the bottom of the stack or until the first Java frame
     while (depth < max_depth) {
-        if (CodeHeap::contains(pc)) {
+        if (CodeHeap::contains(pc) && !(depth == 0 && frame.unwindAtomicStub(pc))) {
             java_ctx->set(pc, sp, fp);
             break;
         }
@@ -124,7 +124,7 @@ int StackWalker::walkDwarf(void* ucontext, const void** callchain, int max_depth
 
     // Walk until the bottom of the stack or until the first Java frame
     while (depth < max_depth) {
-        if (CodeHeap::contains(pc)) {
+        if (CodeHeap::contains(pc) && !(depth == 0 && frame.unwindAtomicStub(pc))) {
             const void* page_start = (const void*)((uintptr_t)pc & ~0xfffUL);
             frame.adjustSP(page_start, pc, sp);
             java_ctx->set(pc, sp, fp);