From 0960ddc6882d3a3445136f9e579947d67c2641dd Mon Sep 17 00:00:00 2001
From: Robo <hop2deep@gmail.com>
Date: Fri, 24 Apr 2026 17:18:10 +0900
Subject: [PATCH] ci: limit the lld concurreny on windows runners (#51310)

---
 .github/actions/build-electron/action.yml     |  9 ++++-
 patches/chromium/.patches                     |  1 +
 ..._gn_arg_to_cap_lld-link_thread_count.patch | 38 +++++++++++++++++++
 3 files changed, 46 insertions(+), 2 deletions(-)
 create mode 100644 patches/chromium/feat_add_win_linker_threads_gn_arg_to_cap_lld-link_thread_count.patch

diff --git a/.github/actions/build-electron/action.yml b/.github/actions/build-electron/action.yml
index 53c7224db9..3c174830f5 100644
--- a/.github/actions/build-electron/action.yml
+++ b/.github/actions/build-electron/action.yml
@@ -40,9 +40,14 @@ runs:
         echo "GN_EXTRA_ARGS=$GN_APPENDED_ARGS" >> $GITHUB_ENV
     - name: Set GN_EXTRA_ARGS for Windows
       shell: bash
-      if: ${{inputs.target-arch != 'x64' && inputs.target-platform == 'win' }}
+      if: ${{ inputs.target-platform == 'win' }}
       run: |
-        GN_APPENDED_ARGS="$GN_EXTRA_ARGS target_cpu=\"${{ inputs.target-arch }}\""
+        # Cap lld-link threads to work around BindFlt concurrency bug in
+        # Windows containers (https://github.com/microsoft/Windows-Containers/issues/635).
+        GN_APPENDED_ARGS="$GN_EXTRA_ARGS win_linker_threads=16"
+        if [ "${{ inputs.target-arch }}" != "x64" ]; then
+          GN_APPENDED_ARGS="$GN_APPENDED_ARGS target_cpu=\"${{ inputs.target-arch }}\""
+        fi
         echo "GN_EXTRA_ARGS=$GN_APPENDED_ARGS" >> $GITHUB_ENV
     - name: Add Clang problem matcher
       shell: bash
diff --git a/patches/chromium/.patches b/patches/chromium/.patches
index 104c1f0bd9..516a3599f4 100644
--- a/patches/chromium/.patches
+++ b/patches/chromium/.patches
@@ -149,3 +149,4 @@ feat_allow_enabling_extensions_on_custom_protocols.patch
 fix_initialize_com_on_desktopmedialistcapturethread_on_windows.patch
 chore_register_node_as_a_dynamic_trace_category_prefix.patch
 fix_allow_reentrancy_on_downloadmanagerimpl_observer_list.patch
+feat_add_win_linker_threads_gn_arg_to_cap_lld-link_thread_count.patch
diff --git a/patches/chromium/feat_add_win_linker_threads_gn_arg_to_cap_lld-link_thread_count.patch b/patches/chromium/feat_add_win_linker_threads_gn_arg_to_cap_lld-link_thread_count.patch
new file mode 100644
index 0000000000..26e9a14d24
--- /dev/null
+++ b/patches/chromium/feat_add_win_linker_threads_gn_arg_to_cap_lld-link_thread_count.patch
@@ -0,0 +1,38 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: deepak1556 <hop2deep@gmail.com>
+Date: Fri, 24 Apr 2026 11:37:59 +0900
+Subject: feat: add win_linker_threads GN arg to cap lld-link thread count
+
+Windows containers using BindFlt have a known bug with high-volume
+concurrent file reads on relative paths. This seems to affect
+the lld-link phase when jumped from 16->32 core ARC runners..
+
+Should be removed when associated container bug is addressed.
+
+diff --git a/build/config/win/BUILD.gn b/build/config/win/BUILD.gn
+index 6f728e380cc7e18230b88a3717679e3cbe2e4a54..9344528f530d485194225c3ce33886a5079ff902 100644
+--- a/build/config/win/BUILD.gn
++++ b/build/config/win/BUILD.gn
+@@ -20,6 +20,11 @@ declare_args() {
+   # Turn this on to have the linker output extra timing information.
+   win_linker_timing = false
+ 
++  # Limit the number of threads used by the linker. 0 means use the default
++  # (all available hardware threads).
++  # Set to a positive integer to cap lld-link's internal thread count.
++  win_linker_threads = 0
++
+   # possible values for target_winuwp_version:
+   #   "10" - Windows UWP 10
+   #   "8.1" - Windows RT 8.1
+@@ -335,6 +340,10 @@ config("common_linker_setup") {
+       "/verbose:incr",
+     ]
+   }
++
++  if (win_linker_threads > 0) {
++    ldflags += [ "/threads:$win_linker_threads" ]
++  }
+ }
+ 
+ config("default_cfg_compiler") {