diff --git a/build/GitVersion.zig b/build/GitVersion.zig
index e5dbf59..ba1fdd3 100644
--- a/build/GitVersion.zig
+++ b/build/GitVersion.zig
@@ -64,8 +64,11 @@ pub fn getVersion(b: *Build, options: Options) []const u8 {
 
 fn findBuildRoot(allocator: std.mem.Allocator, io: std.Io) ![]const u8 {
     var buf: [std.fs.max_path_bytes]u8 = undefined;
-    // `realPath` now returns the length written rather than a slice.
-    const start_len = try std.Io.Dir.cwd().realPath(io, &buf);
+    // Not `Dir.cwd().realPath`: on Linux that resolves the handle through
+    // `/proc/self/fd/{fd}`, and `Dir.cwd()` is the `AT_FDCWD` sentinel (-100)
+    // rather than a real descriptor, so it always fails with `FileNotFound`.
+    // That silently turned every version string into "unknown".
+    const start_len = try std.process.currentPath(io, &buf);
     var cwd: []const u8 = buf[0..start_len];
 
     while (true) {