Fix panic when print stack trace for panic

ostd/src/panicking.rs

@@ -80,6 +80,7 @@ fn print_stack_trace() {
         let data = unsafe { &mut *(arg as *mut CallbackData) };
         data.counter += 1;
         let pc = _Unwind_GetIP(unwind_ctx);
+        if pc > 0 {
             let fde_initial_address = _Unwind_FindEnclosingFunction(pc as *mut c_void) as usize;
             early_println!(
                 "{:4}: fn {:#18x} - pc {:#18x} / registers:",
@@ -87,6 +88,7 @@ fn print_stack_trace() {
                 fde_initial_address,
                 pc,
             );
+        }
         // Print the first 8 general registers for any architecture. The register number follows
         // the DWARF standard.
         for i in 0..8u16 {