From 6f67b1c61a731fa023b393f6cfd2f859897ab6c7 Mon Sep 17 00:00:00 2001
From: Maosu Zhao <maosu.zhao@intel.com>
Date: Wed, 25 Sep 2024 14:33:43 +0800
Subject: [PATCH 1/2] [DeviceSanitizer] Only try to get backtrace symbols when
 needed

---
 source/loader/layers/sanitizer/common.hpp     |  1 +
 .../layers/sanitizer/linux/backtrace.cpp      | 20 +++++++++----------
 source/loader/layers/sanitizer/stacktrace.cpp |  8 +++++++-
 source/loader/layers/sanitizer/stacktrace.hpp |  6 ++++--
 4 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/source/loader/layers/sanitizer/common.hpp b/source/loader/layers/sanitizer/common.hpp
index 2b6a7c22c3..90402b9429 100644
--- a/source/loader/layers/sanitizer/common.hpp
+++ b/source/loader/layers/sanitizer/common.hpp
@@ -127,6 +127,7 @@ inline uint64_t GetSizeAndRedzoneSizeForLocal(uint64_t Size,
             return Result;                                                     \
     }
 
+using BacktraceFrame = void *;
 using BacktraceInfo = std::string;
 
 struct SourceInfo {
diff --git a/source/loader/layers/sanitizer/linux/backtrace.cpp b/source/loader/layers/sanitizer/linux/backtrace.cpp
index b336dc3675..5975515678 100644
--- a/source/loader/layers/sanitizer/linux/backtrace.cpp
+++ b/source/loader/layers/sanitizer/linux/backtrace.cpp
@@ -17,20 +17,20 @@ namespace ur_sanitizer_layer {
 StackTrace GetCurrentBacktrace() {
     void *Frames[MAX_BACKTRACE_FRAMES];
     int FrameCount = backtrace(Frames, MAX_BACKTRACE_FRAMES);
-    char **Symbols = backtrace_symbols(Frames, FrameCount);
-
-    if (Symbols == nullptr) {
-        return StackTrace();
-    }
 
     StackTrace Stack;
-    for (int i = 0; i < FrameCount; i++) {
-        BacktraceInfo addr_info(Symbols[i]);
-        Stack.stack.emplace_back(addr_info);
-    }
-    free(Symbols);
+    Stack.stack =
+        std::vector<BacktraceFrame>(&Frames[0], &Frames[FrameCount - 1]);
 
     return Stack;
 }
 
+char **GetBacktraceSymbols(const std::vector<BacktraceFrame> &BacktraceFrames) {
+    assert(!BacktraceFrames.empty());
+
+    char **BacktraceSymbols =
+        backtrace_symbols(&BacktraceFrames[0], BacktraceFrames.size());
+    return BacktraceSymbols;
+}
+
 } // namespace ur_sanitizer_layer
diff --git a/source/loader/layers/sanitizer/stacktrace.cpp b/source/loader/layers/sanitizer/stacktrace.cpp
index 38bef94811..8adaa2cd34 100644
--- a/source/loader/layers/sanitizer/stacktrace.cpp
+++ b/source/loader/layers/sanitizer/stacktrace.cpp
@@ -86,7 +86,11 @@ void StackTrace::print() const {
 
     unsigned index = 0;
 
-    for (auto &BI : stack) {
+    char **BacktraceSymbols = GetBacktraceSymbols(stack);
+
+    for (size_t i = 0; i < stack.size(); i++) {
+        BacktraceInfo BI = BacktraceSymbols[i];
+
         // Skip runtime modules
         if (Contains(BI, "libsycl.so") ||
             Contains(BI, "libpi_unified_runtime.so") ||
@@ -123,6 +127,8 @@ void StackTrace::print() const {
         ++index;
     }
     getContext()->logger.always("");
+
+    free(BacktraceSymbols);
 }
 
 } // namespace ur_sanitizer_layer
diff --git a/source/loader/layers/sanitizer/stacktrace.hpp b/source/loader/layers/sanitizer/stacktrace.hpp
index 31b661cc7d..a98c310473 100644
--- a/source/loader/layers/sanitizer/stacktrace.hpp
+++ b/source/loader/layers/sanitizer/stacktrace.hpp
@@ -18,14 +18,16 @@
 
 namespace ur_sanitizer_layer {
 
-constexpr size_t MAX_BACKTRACE_FRAMES = 64;
+constexpr size_t MAX_BACKTRACE_FRAMES = 48;
 
 struct StackTrace {
-    std::vector<BacktraceInfo> stack;
+    std::vector<BacktraceFrame> stack;
 
     void print() const;
 };
 
 StackTrace GetCurrentBacktrace();
 
+char **GetBacktraceSymbols(const std::vector<BacktraceFrame> &BacktraceFrames);
+
 } // namespace ur_sanitizer_layer

From e36e1b6e4e5be4248c78129980645a3ec00965c1 Mon Sep 17 00:00:00 2001
From: Maosu Zhao <maosu.zhao@intel.com>
Date: Wed, 25 Sep 2024 15:23:24 +0800
Subject: [PATCH 2/2] update as per comments

---
 source/loader/layers/sanitizer/linux/backtrace.cpp | 2 +-
 source/loader/layers/sanitizer/stacktrace.hpp      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/source/loader/layers/sanitizer/linux/backtrace.cpp b/source/loader/layers/sanitizer/linux/backtrace.cpp
index 5975515678..b746348205 100644
--- a/source/loader/layers/sanitizer/linux/backtrace.cpp
+++ b/source/loader/layers/sanitizer/linux/backtrace.cpp
@@ -15,7 +15,7 @@
 namespace ur_sanitizer_layer {
 
 StackTrace GetCurrentBacktrace() {
-    void *Frames[MAX_BACKTRACE_FRAMES];
+    BacktraceFrame Frames[MAX_BACKTRACE_FRAMES];
     int FrameCount = backtrace(Frames, MAX_BACKTRACE_FRAMES);
 
     StackTrace Stack;
diff --git a/source/loader/layers/sanitizer/stacktrace.hpp b/source/loader/layers/sanitizer/stacktrace.hpp
index a98c310473..57811bba01 100644
--- a/source/loader/layers/sanitizer/stacktrace.hpp
+++ b/source/loader/layers/sanitizer/stacktrace.hpp
@@ -18,7 +18,7 @@
 
 namespace ur_sanitizer_layer {
 
-constexpr size_t MAX_BACKTRACE_FRAMES = 48;
+constexpr size_t MAX_BACKTRACE_FRAMES = 64;
 
 struct StackTrace {
     std::vector<BacktraceFrame> stack;