diff --git a/src/core/SkASAN.h b/src/core/SkASAN.h
index 84b0f0c633..40870a4879 100644
--- a/src/core/SkASAN.h
+++ b/src/core/SkASAN.h
@@ -22,7 +22,7 @@
 #endif
 
 // Typically declared in LLVM's asan_interface.h.
-#if SK_SANITIZE_ADDRESS
+#ifdef SK_SANITIZE_ADDRESS
 extern "C" {
     void __asan_poison_memory_region(void const volatile *addr, size_t size);
     void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
@@ -33,13 +33,13 @@ extern "C" {
 // unpoison chunks of arena memory as they are parceled out. Consider leaving gaps between blocks
 // to detect buffer overrun.
 static inline void sk_asan_poison_memory_region(void const volatile *addr, size_t size) {
-#if SK_SANITIZE_ADDRESS
+#ifdef SK_SANITIZE_ADDRESS
     __asan_poison_memory_region(addr, size);
 #endif
 }
 
 static inline void sk_asan_unpoison_memory_region(void const volatile *addr, size_t size) {
-#if SK_SANITIZE_ADDRESS
+#ifdef SK_SANITIZE_ADDRESS
     __asan_unpoison_memory_region(addr, size);
 #endif
 }
diff --git a/src/gpu/GrMemoryPool.cpp b/src/gpu/GrMemoryPool.cpp
index 2686cbf7b0..0a20527591 100644
--- a/src/gpu/GrMemoryPool.cpp
+++ b/src/gpu/GrMemoryPool.cpp
@@ -8,6 +8,7 @@
 #include "src/gpu/GrMemoryPool.h"
 
 #include "include/private/SkTPin.h"
+#include "src/core/SkASAN.h"
 #include "src/gpu/ops/GrOp.h"
 
 #ifdef SK_DEBUG
@@ -69,8 +70,13 @@ void* GrMemoryPool::allocate(size_t size) {
     // Update live count within the block
     alloc.fBlock->setMetadata(alloc.fBlock->metadata() + 1);
 
-#ifdef SK_DEBUG
+#if defined(SK_SANITIZE_ADDRESS)
+    sk_asan_poison_memory_region(&header->fSentinel, sizeof(header->fSentinel));
+#elif defined(SK_DEBUG)
     header->fSentinel = GrBlockAllocator::kAssignedMarker;
+#endif
+
+#if defined(SK_DEBUG)
     header->fID = []{
         static std::atomic<int> nextID{1};
         return nextID++;
@@ -89,16 +95,20 @@ void GrMemoryPool::release(void* p) {
     // NOTE: if we needed it, (p - block) would equal the original alignedOffset value returned by
     // GrBlockAllocator::allocate()
     Header* header = reinterpret_cast<Header*>(reinterpret_cast<intptr_t>(p) - sizeof(Header));
+
+#if defined(SK_SANITIZE_ADDRESS)
+    sk_asan_unpoison_memory_region(&header->fSentinel, sizeof(header->fSentinel));
+#elif defined(SK_DEBUG)
     SkASSERT(GrBlockAllocator::kAssignedMarker == header->fSentinel);
-
-    GrBlockAllocator::Block* block = fAllocator.owningBlock<kAlignment>(header, header->fStart);
-
-#ifdef SK_DEBUG
     header->fSentinel = GrBlockAllocator::kFreedMarker;
+#endif
+
+#if defined(SK_DEBUG)
     fAllocatedIDs.remove(header->fID);
     fAllocationCount--;
 #endif
 
+    GrBlockAllocator::Block* block = fAllocator.owningBlock<kAlignment>(header, header->fStart);
     int alive = block->metadata();
     if (alive == 1) {
         // This was last allocation in the block, so remove it
diff --git a/src/gpu/GrMemoryPool.h b/src/gpu/GrMemoryPool.h
index 5c612ea790..9ce408f787 100644
--- a/src/gpu/GrMemoryPool.h
+++ b/src/gpu/GrMemoryPool.h
@@ -106,12 +106,14 @@ private:
     // Per-allocation overhead so that GrMemoryPool can always identify the block owning each and
     // release all occupied bytes, including any resulting from alignment padding.
     struct Header {
-#ifdef SK_DEBUG
-        int fSentinel; // known value to check for memory stomping (e.g., (CD)*)
-        int fID;       // ID that can be used to track down leaks by clients.
-#endif
         int fStart;
         int fEnd;
+#if defined(SK_DEBUG)
+        int fID;       // ID that can be used to track down leaks by clients.
+#endif
+#if defined(SK_DEBUG) || defined(SK_SANITIZE_ADDRESS)
+        int fSentinel; // set to a known value to check for memory stomping; poisoned in ASAN mode
+#endif
     };
 
     GrMemoryPool(size_t preallocSize, size_t minAllocSize);