Fix skips

Signed-off-by: Pablo Galindo <[email protected]>

Author: pablogsal

src/memray/_memray/ghost_stack/src/ghost_stack.cpp

@@ -251,7 +251,7 @@ class GhostStackImpl {
         size_t count = (available < max_frames) ? available : max_frames;
 
         for (size_t i = 0; i < count; ++i) {
-            buffer[i] = reinterpret_cast<void*>(entries_[i].ip);
+            buffer[i] = reinterpret_cast<void*>(entries_[count - 1 - i].ip);
         }
 
         LOG_DEBUG("Fast path: %zu frames\n", count);
@@ -278,15 +278,6 @@ class GhostStackImpl {
         unw_getcontext(&ctx);
         unw_init_local(&cursor, &ctx);
 
-        // Skip internal frames (platform-specific due to backtrace/libunwind differences)
-#ifdef __APPLE__
-        // macOS: Skip fewer frames due to backtrace()/libunwind difference
-        for (int i = 0; i < 1 && unw_step(&cursor) > 0; ++i) {}
-#else
-        // Linux: Skip internal frames (this function + backtrace)
-        for (int i = 0; i < 3 && unw_step(&cursor) > 0; ++i) {}
-#endif
-
         // Process frames: read current frame, then step to next
         // Note: After skip loop, cursor is positioned AT the first frame we want
         // We need to read first, then step (not step-then-read)

src/memray/_memray/tracking_api.h

@@ -27,6 +27,11 @@
 
 #ifdef MEMRAY_HAS_GHOST_STACK
 #    include "ghost_stack.h"
+#if defined(__linux__)
+# define GHOST_STACK_SKIP_FRAMES 2
+#elif defined(__APPLE__)
+# define GHOST_STACK_SKIP_FRAMES 1
+#endif
 #endif
 
 #include "frame_tree.h"
@@ -197,7 +202,11 @@ class NativeTrace
             d_data.resize(d_data.size() * 2);
         }
         d_size = size > skip ? size - skip : 0;
+#ifdef MEMRAY_HAS_GHOST_STACK
+        d_skip = skip + (s_use_fast_unwind ? GHOST_STACK_SKIP_FRAMES : 0);
+#else
         d_skip = skip;
+#endif
         return d_size > 0;
     }