diff --git a/gpu/command_buffer/service/shared_image/dawn_copy_strategy.cc b/gpu/command_buffer/service/shared_image/dawn_copy_strategy.cc
index e56810f86a9b3..da672accdf720 100644
--- a/gpu/command_buffer/service/shared_image/dawn_copy_strategy.cc
+++ b/gpu/command_buffer/service/shared_image/dawn_copy_strategy.cc
@@ -334,14 +334,19 @@ bool DawnCopyStrategy::CopyFromTextureToBacking(wgpu::Texture src_texture,
        plane_index < static_cast<int>(staging_buffers.size()); ++plane_index) {
     const auto& staging_buffer_entry = staging_buffers[plane_index];
 
-    bool success = false;
+    // The MapAsync callback is WaitAnyOnly: if WaitAny returns non-Success
+    // (e.g. TimedOut on device loss), Dawn retains the callback until
+    // ~EventManager and fires it then. Heap-allocate the result so the
+    // callback never writes to a dead stack slot. The capturing-lambda
+    // overload of MapAsync heap-allocates the closure and frees it when the
+    // callback fires.
+    auto success = std::make_shared<bool>(false);
     wgpu::FutureWaitInfo wait_info = {staging_buffer_entry.buffer.MapAsync(
         wgpu::MapMode::Read, 0, wgpu::kWholeMapSize,
         wgpu::CallbackMode::WaitAnyOnly,
-        [](wgpu::MapAsyncStatus status, wgpu::StringView, bool* success) {
+        [success](wgpu::MapAsyncStatus status, wgpu::StringView) {
           *success = status == wgpu::MapAsyncStatus::Success;
-        },
-        &success)};
+        })};
 
     if (device.GetAdapter().GetInstance().WaitAny(1, &wait_info, UINT64_MAX) !=
         wgpu::WaitStatus::Success) {
@@ -349,7 +354,7 @@ bool DawnCopyStrategy::CopyFromTextureToBacking(wgpu::Texture src_texture,
       return false;
     }
 
-    if (!wait_info.completed || !success) {
+    if (!wait_info.completed || !*success) {
       LOG(ERROR) << "MapAsync did not yield a readable mapping.";
       return false;
     }