why are we getting the current process twice

Author: workingjubilee

src/backtrace/win32.rs

@@ -94,6 +94,9 @@ impl Frame {
 #[repr(C, align(16))] // required by `CONTEXT`, is a FIXME in windows metadata right now
 struct MyContext(CONTEXT);
 
+/// # Safety
+/// This function makes many calls to dbghelp, which must be called in a single-threaded fashion.
+/// Therefore, it is unsound to call this function concurrently without synchronization.
 #[inline(always)]
 pub unsafe fn trace(cb: &mut dyn FnMut(&super::Frame) -> bool) {
     // Allocate necessary structures for doing the stack walk
@@ -112,8 +115,6 @@ pub unsafe fn trace(cb: &mut dyn FnMut(&super::Frame) -> bool) {
     let function_table_access = dbghelp.SymFunctionTableAccess64();
     let get_module_base = dbghelp.SymGetModuleBase64();
 
-    let process_handle = unsafe { GetCurrentProcess() };
-
     // Attempt to use `StackWalkEx` if we can, but fall back to `StackWalk64`
     // since it's in theory supported on more systems.
     match unsafe { (*dbghelp.dbghelp()).StackWalkEx() } {
@@ -147,7 +148,7 @@ pub unsafe fn trace(cb: &mut dyn FnMut(&super::Frame) -> bool) {
                 0,
             ) == TRUE }
             {
-                frame.inner.base_address = unsafe { get_module_base(process_handle, frame.ip() as _) as _ };
+                frame.inner.base_address = unsafe { get_module_base(process, frame.ip() as _) as _ };
 
                 if !cb(&frame) {
                     break;
@@ -180,7 +181,7 @@ pub unsafe fn trace(cb: &mut dyn FnMut(&super::Frame) -> bool) {
                 None,
             ) == TRUE }
             {
-                frame.inner.base_address = unsafe { get_module_base(process_handle, frame.ip() as _) as _ };
+                frame.inner.base_address = unsafe { get_module_base(process, frame.ip() as _) as _ };
 
                 if !cb(&frame) {
                     break;