[v12.x backport] doc: deprecate process.umask() with no arguments

doc/api/deprecations.md

@@ -2542,6 +2542,24 @@ accordingly instead to avoid the ambigiuty.
 To maintain existing behaviour `response.finished` should be replaced with
 `response.writableEnded`.
 
+<a id="DEP0139"></a>
+### DEP0139: `process.umask()` with no arguments
+<!-- YAML
+changes:
+  - version:
+    - REPLACEME
+    - v14.0.0
+    pr-url: https://github.com/nodejs/node/pull/32499
+    description: Documentation-only deprecation.
+-->
+
+Type: Documentation-only
+
+Calling `process.umask()` with no argument causes the process-wide umask to be
+written twice. This introduces a race condition between threads, and is a
+potential security vulnerability. There is no safe, cross-platform alternative
+API.
+
 [`--http-parser=legacy`]: cli.html#cli_http_parser_library
 [`--pending-deprecation`]: cli.html#cli_pending_deprecation
 [`--throw-deprecation`]: cli.html#cli_throw_deprecation

doc/api/process.md

@@ -2393,17 +2393,35 @@ documentation for the [`'warning'` event][process_warning] and the
 [`emitWarning()` method][process_emit_warning] for more information about this
 flag's behavior.
 
-## `process.umask([mask])`
+## `process.umask()`
+<!-- YAML
+added: v0.1.19
+changes:
+  - version:
+    - REPLACEME
+    - v14.0.0
+    pr-url: https://github.com/nodejs/node/pull/32499
+    description: Calling `process.umask()` with no arguments is deprecated.
+
+-->
+
+> Stability: 0 - Deprecated. Calling `process.umask()` with no argument causes
+> the process-wide umask to be written twice. This introduces a race condition
+> between threads, and is a potential security vulnerability. There is no safe,
+> cross-platform alternative API.
+
+`process.umask()` returns the Node.js process's file mode creation mask. Child
+processes inherit the mask from the parent process.
+
+## `process.umask(mask)`
 <!-- YAML
 added: v0.1.19
 -->
 
 * `mask` {string|integer}
 
-The `process.umask()` method sets or returns the Node.js process's file mode
-creation mask. Child processes inherit the mask from the parent process. Invoked
-without an argument, the current mask is returned, otherwise the umask is set to
-the argument value and the previous mask is returned.
+`process.umask(mask)` sets the Node.js process's file mode creation mask. Child
+processes inherit the mask from the parent process. Returns the previous mask.
 
 ```js
 const newmask = 0o022;
@@ -2413,8 +2431,7 @@ console.log(
 );
 ```
 
-[`Worker`][] threads are able to read the umask, however attempting to set the
-umask will result in a thrown exception.
+In [`Worker`][] threads, `process.umask(mask)` will throw an exception.
 
 ## `process.uptime()`
 <!-- YAML