diff --git a/.gitignore b/.gitignore
index 86ee4cf0..0c890a3a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,7 +5,9 @@
 .*.kak.*
 src/kak
 src/kak.debug
+src/kak.debug.san_*
 src/kak.opt
+src/kak.opt.san_*
 src/.version*
 src/.*.json
 doc/kak.1.gz
diff --git a/src/file.cc b/src/file.cc
index a2ad279b..58eb9284 100644
--- a/src/file.cc
+++ b/src/file.cc
@@ -252,13 +252,14 @@ bool regular_file_exists(StringView filename)
            (st.st_mode & S_IFMT) == S_IFREG;
 }
 
+template<bool atomic>
 void write(int fd, StringView data)
 {
     const char* ptr = data.data();
     ssize_t count   = (int)data.length();
 
     int flags = fcntl(fd, F_GETFL, 0);
-    if (EventManager::has_instance())
+    if (not atomic and EventManager::has_instance())
         fcntl(fd, F_SETFL, flags | O_NONBLOCK);
     auto restore_flags = on_scope_end([&] { fcntl(fd, F_SETFL, flags); });
 
@@ -269,12 +270,15 @@ void write(int fd, StringView data)
             ptr += written;
             count -= written;
         }
-        else if (errno == EAGAIN and EventManager::has_instance())
+        else if (errno == EAGAIN and not atomic and EventManager::has_instance())
             EventManager::instance().handle_next_events(EventMode::Urgent, nullptr, false);
         else
             throw file_access_error(format("fd: {}", fd), strerror(errno));
     }
 }
+template void write<true>(int fd, StringView data);
+template void write<false>(int fd, StringView data);
+
 
 void write_to_file(StringView filename, StringView data)
 {
@@ -295,7 +299,7 @@ void write_buffer_to_fd(Buffer& buffer, int fd)
         eoldata = "\n";
 
 
-    BufferedWriter writer{fd};
+    BufferedWriter<false> writer{fd};
     if (buffer.options()["BOM"].get<ByteOrderMark>() == ByteOrderMark::Utf8)
         writer.write("\xEF\xBB\xBF");
 
diff --git a/src/file.hh b/src/file.hh
index 1d9391fb..65abd3c8 100644
--- a/src/file.hh
+++ b/src/file.hh
@@ -39,6 +39,7 @@ bool fd_readable(int fd);
 bool fd_writable(int fd);
 String read_fd(int fd, bool text = false);
 String read_file(StringView filename, bool text = false);
+template<bool force_blocking = false>
 void write(int fd, StringView data);
 void write_to_file(StringView filename, StringView data);
 
@@ -121,7 +122,7 @@ CandidateList complete_filename(StringView prefix, const Regex& ignore_regex,
 
 CandidateList complete_command(StringView prefix, ByteCount cursor_pos = -1);
 
-template<int buffer_size = 4096>
+template<bool atomic, int buffer_size = 4096>
 struct BufferedWriter
 {
     BufferedWriter(int fd)
@@ -149,7 +150,7 @@ struct BufferedWriter
 
     void flush()
     {
-        Kakoune::write(m_fd, {m_buffer, m_pos});
+        Kakoune::write<atomic>(m_fd, {m_buffer, m_pos});
         m_pos = 0;
     }
 
diff --git a/src/terminal_ui.cc b/src/terminal_ui.cc
index d411dd67..9685129a 100644
--- a/src/terminal_ui.cc
+++ b/src/terminal_ui.cc
@@ -208,7 +208,7 @@ void TerminalUI::Window::draw(DisplayCoord pos,
         lines[(int)pos.line].append({}, size.column - pos.column, default_face);
 }
 
-struct Writer : BufferedWriter<>
+struct Writer : BufferedWriter<true>
 {
     using Writer::BufferedWriter::BufferedWriter;
     ~Writer() noexcept(false) = default;
diff --git a/test/regression/0-mouse-during-insert/script b/test/regression/0-mouse-during-insert/script
index 5ce30601..94a40c9b 100644
--- a/test/regression/0-mouse-during-insert/script
+++ b/test/regression/0-mouse-during-insert/script
@@ -10,3 +10,6 @@ ui_in '{ "jsonrpc": "2.0", "method": "mouse_release", "params": [ "left", 0, 4 ]
 sleep .1
 ui_in '{ "jsonrpc": "2.0", "method": "keys", "params": [ "c<esc>" ] }'
 sleep .1
+if [ -n "$CI" ]; then
+	sleep 1
+fi