From 677e905a9627a1adad7c25843d597c908df6b95e Mon Sep 17 00:00:00 2001
From: MAEDA Go <maeda@farend.jp>
Date: Wed, 26 Aug 2026 18:56:42 +0900
Subject: [PATCH 2/2] Fix the gs process surviving when PDF thumbnail
 generation times out.

---
 lib/redmine/thumbnail.rb     | 14 ++++++++++++--
 test/unit/attachment_test.rb | 27 +++++++++++++++++++++------
 2 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/lib/redmine/thumbnail.rb b/lib/redmine/thumbnail.rb
index 8d89ae496..d6f354aff 100644
--- a/lib/redmine/thumbnail.rb
+++ b/lib/redmine/thumbnail.rb
@@ -58,7 +58,12 @@ module Redmine
         pid = nil
         begin
           Timeout.timeout(Redmine::Configuration['thumbnails_generation_timeout'].to_i) do
-            pid = Process.spawn(cmd)
+            # Run the command in its own process group so that the whole
+            # process tree (eg. the gs process spawned by convert for PDF
+            # files) can be killed on timeout. Process groups are not
+            # available on Windows.
+            spawn_options = Redmine::Platform.mswin? ? {} : {:pgroup => true}
+            pid = Process.spawn(cmd, spawn_options)
             _, status = Process.wait2(pid)
             unless status.success?
               logger.error("Creating thumbnail failed (#{status.exitstatus}):\nCommand: #{cmd}")
@@ -67,7 +72,12 @@ module Redmine
           end
         rescue Timeout::Error
           if pid
-            Process.kill('KILL', pid)
+            begin
+              # A negative pid sends the signal to the whole process group
+              Process.kill('KILL', Redmine::Platform.mswin? ? pid : -pid)
+            rescue Errno::ESRCH
+              # The process is already gone
+            end
             Process.detach(pid)
           end
           logger.error("Creating thumbnail timed out:\nCommand: #{cmd}")
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index 820feafde..7cc658c8e 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -787,24 +787,39 @@ class AttachmentTest < ActiveSupport::TestCase
       set_tmp_attachments_directory
     end

-    def test_thumbnail_should_timeout
+    def test_thumbnail_should_kill_and_detach_process_group_on_timeout
       dummy_pid = 37530
-      Process.stubs(:spawn).returns(dummy_pid)
-      Process.stubs(:wait2).raises(Timeout::Error)
-      Process.stubs(:kill).returns(1)
-      Process.stubs(:wait).returns(dummy_pid)
+
+      Redmine::Platform.stubs(:mswin?).returns(false)
+      Redmine::Thumbnail.stubs(:gs_available?).returns(true)
+      Process.expects(:spawn).
+        with(anything, {:pgroup => true}).
+        returns(dummy_pid)
+      Process.expects(:wait2).
+        with(dummy_pid).
+        raises(Timeout::Error)
+      # A negative pid sends the signal to the whole process group so that
+      # child processes of convert (eg. gs) are killed as well
+      Process.expects(:kill).
+        with('KILL', -dummy_pid).
+        returns(1)
+      Process.expects(:detach).
+        with(dummy_pid)
       Rails.logger.expects(:error).with(regexp_matches(/Creating thumbnail timed out/))

       set_fixtures_attachments_directory
       Attachment.clear_thumbnails

-      attachment = Attachment.find(16)
+      # Use a PDF attachment because convert spawns a Ghostscript (gs)
+      # child process for PDFs, which must not survive the timeout
+      attachment = Attachment.find(23)
       thumbnail = attachment.thumbnail

       assert_nil thumbnail
     ensure
       set_tmp_attachments_directory
     end
+
   else
     puts '(ImageMagick convert not available)'
   end
--
2.55.0