diff --git a/build/config/linux/pkg_config.gni b/build/config/linux/pkg_config.gni
index 14c4ee8dcf..3deef2ba22 100644
--- a/build/config/linux/pkg_config.gni
+++ b/build/config/linux/pkg_config.gni
@@ -57,7 +57,7 @@ if (sysroot != "") {
   # Pass the sysroot if we're using one (it requires the CPU arch also).
   pkg_config_args += [
     "-s",
-    rebase_path(sysroot),
+    rebase_path(sysroot, "", root_build_dir),
     "-a",
     current_cpu,
   ]
diff --git a/build/config/sysroot.gni b/build/config/sysroot.gni
index 7987e519d1..07ad913695 100644
--- a/build/config/sysroot.gni
+++ b/build/config/sysroot.gni
@@ -21,13 +21,13 @@ if (current_toolchain == default_toolchain && target_sysroot != "") {
   sysroot = target_sysroot
 } else if (is_android) {
   import("//build/config/android/config.gni")
-  sysroot = rebase_path("$llvm_android_toolchain_root/sysroot")
+  sysroot = rebase_path("$llvm_android_toolchain_root/sysroot", root_build_dir)
 } else if (is_linux && !is_chromeos) {
   if (use_default_linux_sysroot && !is_fuchsia) {
     if (current_cpu == "x64") {
-      sysroot = rebase_path("//build/linux/debian_sid_amd64-sysroot")
+      sysroot = rebase_path("//build/linux/debian_sid_amd64-sysroot", root_build_dir)
     } else {
-      sysroot = rebase_path("//build/linux/debian_sid_arm64-sysroot")
+      sysroot = rebase_path("//build/linux/debian_sid_arm64-sysroot", root_build_dir)
     }
     assert(
         exec_script("//build/dir_exists.py", [ sysroot ], "string") == "True",