[DeviceAsan] Enlarge nullpointer redzone to better detect problem (#2243)

Author: yingcong-wu

source/loader/layers/sanitizer/asan_report.cpp

@@ -103,9 +103,10 @@ void ReportGenericError(const DeviceSanitizerReport &Report,
     // Try to demangle the kernel name
     KernelName = DemangleName(KernelName);
 
-    getContext()->logger.always("\n====ERROR: DeviceSanitizer: {} on {}",
+    getContext()->logger.always("\n====ERROR: DeviceSanitizer: {} on {} ({})",
                                 ToString(Report.ErrorType),
-                                ToString(Report.MemoryType));
+                                ToString(Report.MemoryType),
+                                (void *)Report.Address);
     getContext()->logger.always(
         "{} of size {} at kernel <{}> LID({}, {}, {}) GID({}, "
         "{}, {})",

source/loader/layers/sanitizer/asan_shadow.cpp

@@ -50,7 +50,10 @@ ur_result_t ShadowMemoryCPU::Setup() {
         ShadowEnd = ShadowBegin + ShadowSize;
 
         // Set shadow memory for null pointer
-        auto URes = EnqueuePoisonShadow({}, 0, 1, kNullPointerRedzoneMagic);
+        // For CPU, we use a typical page size of 4K bytes.
+        constexpr size_t NullptrRedzoneSize = 4096;
+        auto URes = EnqueuePoisonShadow({}, 0, NullptrRedzoneSize,
+                                        kNullPointerRedzoneMagic);
         if (URes != UR_RESULT_SUCCESS) {
             getContext()->logger.error("EnqueuePoisonShadow(NullPointerRZ): {}",
                                        URes);
@@ -111,9 +114,12 @@ ur_result_t ShadowMemoryGPU::Setup() {
         }
 
         // Set shadow memory for null pointer
+        // For GPU, wu use up to 1 page of shadow memory
+        const size_t NullptrRedzoneSize =
+            GetVirtualMemGranularity(Context, Device) << ASAN_SHADOW_SCALE;
         ManagedQueue Queue(Context, Device);
-
-        Result = EnqueuePoisonShadow(Queue, 0, 1, kNullPointerRedzoneMagic);
+        Result = EnqueuePoisonShadow(Queue, 0, NullptrRedzoneSize,
+                                     kNullPointerRedzoneMagic);
         if (Result != UR_RESULT_SUCCESS) {
             getContext()->logger.error("EnqueuePoisonShadow(NullPointerRZ): {}",
                                        Result);