2 files changed, 20 insertions, 3 deletions
diff --git a/source/blender/editors/interface/interface_align.c b/source/blender/editors/interface/interface_align.c
index 59436276277..8edae5d8740 100644
--- a/source/blender/editors/interface/interface_align.c
+++ b/source/blender/editors/interface/interface_align.c
@@ -31,6 +31,8 @@
 
 #include "interface_intern.h"
 
+#include "MEM_guardedalloc.h"
+
 #ifdef USE_UIBUT_SPATIAL_ALIGN
 
 /**
@@ -416,7 +418,16 @@ void ui_block_align_calc(uiBlock *block, const ARegion *region)
     return;
   }
 
-  butal_array = alloca(sizeof(*butal_array) * (size_t)num_buttons);
+  /* Note that this is typically less than ~20, and almost always under ~100.
+   * Even so, we can't ensure this value won't exceed available stack memory.
+   * Fallback to allocation instead of using #alloca, see: T78636. */
+  ButAlign butal_array_buf[256];
+  if (num_buttons <= ARRAY_SIZE(butal_array_buf)) {
+    butal_array = butal_array_buf;
+  }
+  else {
+    butal_array = MEM_mallocN(sizeof(*butal_array) * num_buttons, __func__);
+  }
   memset(butal_array, 0, sizeof(*butal_array) * (size_t)num_buttons);
 
   /* Second loop: we initialize our ButAlign data for each button. */
@@ -515,6 +526,9 @@ void ui_block_align_calc(uiBlock *block, const ARegion *region)
       }
     }
   }
+  if (butal_array_buf != butal_array) {
+    MEM_freeN(butal_array);
+  }
 }
 
 #  undef SIDE_TO_UI_BUT_ALIGN
diff --git a/source/blender/editors/interface/interface_layout.c b/source/blender/editors/interface/interface_layout.c
index 858b48ba9fa..f027a62cbfd 100644
--- a/source/blender/editors/interface/interface_layout.c
+++ b/source/blender/editors/interface/interface_layout.c
@@ -947,8 +947,11 @@ static uiBut *ui_item_with_label(uiLayout *layout,
   const bool use_prop_sep = ((layout->item.flag & UI_ITEM_PROP_SEP) != 0);
 #endif
 
-  /* Always align item with label since text is already given enough space not to overlap. */
-  sub = uiLayoutRow(layout, true);
+  /* Previously 'align' was enabled to make sure the label is spaced closely to the button.
+   * Set the space to zero instead as aligning a large number of labels can end up aligning
+   * thousands of buttons when displaying key-map search (a heavy operation), see: T78636. */
+  sub = uiLayoutRow(layout, false);
+  sub->space = 0;
   UI_block_layout_set_current(block, sub);
 
 #ifdef UI_PROP_DECORATE