From d74d77226c65ff6412e4c6c94bf2e620ca37e8c3 Mon Sep 17 00:00:00 2001
From: Bartosz Taudul <wolf@nereid.pl>
Date: Sat, 25 Jul 2026 16:43:43 +0200
Subject: [PATCH] Guard against empty synthetic call stacks in parents frame
 trees.

A sample with a single-frame call stack already produces a zero-length parent
stack, and GetParentsCallstackFrameTree{BottomUp,TopDown} call cs.back() /
cs.front() on it, resulting in UB.
---
 profiler/src/profiler/TracyView_FrameTree.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/profiler/src/profiler/TracyView_FrameTree.cpp b/profiler/src/profiler/TracyView_FrameTree.cpp
index 8ab142bb..f664ebb4 100644
--- a/profiler/src/profiler/TracyView_FrameTree.cpp
+++ b/profiler/src/profiler/TracyView_FrameTree.cpp
@@ -248,6 +248,7 @@ unordered_flat_map<uint64_t, CallstackFrameTree> View::GetParentsCallstackFrameT
         for( auto& path : stacks )
         {
             auto& cs = m_worker.GetSyntheticCallstack( path.first );
+            if( cs.empty() ) continue;
             auto base = cs.back();
             auto treePtr = GetParentFrameTreeItemGroup( root, base, m_worker );
             if( treePtr )
@@ -267,6 +268,7 @@ unordered_flat_map<uint64_t, CallstackFrameTree> View::GetParentsCallstackFrameT
         for( auto& path : stacks )
         {
             auto& cs = m_worker.GetSyntheticCallstack( path.first );
+            if( cs.empty() ) continue;
             auto base = cs.back();
             auto treePtr = GetFrameTreeItemNoGroup( root, base );
             treePtr->count += path.second;
@@ -378,6 +380,7 @@ unordered_flat_map<uint64_t, CallstackFrameTree> View::GetParentsCallstackFrameT
         for( auto& path : stacks )
         {
             auto& cs = m_worker.GetSyntheticCallstack( path.first );
+            if( cs.empty() ) continue;
             auto base = cs.front();
             auto treePtr = GetParentFrameTreeItemGroup( root, base, m_worker );
             if( treePtr )
@@ -397,6 +400,7 @@ unordered_flat_map<uint64_t, CallstackFrameTree> View::GetParentsCallstackFrameT
         for( auto& path : stacks )
         {
             auto& cs = m_worker.GetSyntheticCallstack( path.first );
+            if( cs.empty() ) continue;
             auto base = cs.front();
             auto treePtr = GetFrameTreeItemNoGroup( root, base );
             treePtr->count += path.second;