From c87476dd5da5ba50e6f74e35e42151fbeea3601e Mon Sep 17 00:00:00 2001
From: kobalicek <kobalicek.petr@gmail.com>
Date: Mon, 27 Feb 2023 20:41:08 +0100
Subject: [PATCH] [Bug] Use ReadWrite scope to fill memory in
 JitAllocator::shrink() (MAP_JIT)

---
 src/asmjit/core/jitallocator.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/asmjit/core/jitallocator.cpp b/src/asmjit/core/jitallocator.cpp
index b3651d1..313736c 100644
--- a/src/asmjit/core/jitallocator.cpp
+++ b/src/asmjit/core/jitallocator.cpp
@@ -915,8 +915,13 @@ Error JitAllocator::shrink(void* rxPtr, size_t newSize) noexcept {
     block->markShrunkArea(areaStart + areaShrunkSize, areaEnd);
 
     // Fill released memory if the secure mode is enabled.
-    if (Support::test(impl->options, JitAllocatorOptions::kFillUnusedMemory))
-      JitAllocatorImpl_fillPattern(block->rwPtr() + (areaStart + areaShrunkSize) * pool->granularity, fillPattern(), areaDiff * pool->granularity);
+    if (Support::test(impl->options, JitAllocatorOptions::kFillUnusedMemory)) {
+      uint8_t* spanPtr = block->rwPtr() + (areaStart + areaShrunkSize) * pool->granularity;
+      size_t spanSize = areaDiff * pool->granularity;
+
+      VirtMem::ProtectJitReadWriteScope scope(spanPtr, spanSize);
+      JitAllocatorImpl_fillPattern(spanPtr, fillPattern(), spanSize);
+    }
   }
 
   return kErrorOk;