Revert "Restore parent mount namespace before executing a child process"

This reverts commit a0ef21262f4d5652bfb65cfacaec01d89c475a93. This
doesn't work in 'nix run' and nix-shell because setns() fails in
multithreaded programs, and Boehm GC mark threads are uncancellable.

Fixes #2646.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index 11ea3b1f7..618895d38 100755
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -401,6 +401,8 @@ static void _main(int argc, char * * argv)
             } else
                 env[var.first] = var.second;
 
+        restoreAffinity();
+
         /* Run a shell using the derivation's environment.  For
            convenience, source $stdenv/setup to setup additional
            environment variables and shell functions.  Also don't
@@ -444,9 +446,7 @@ static void _main(int argc, char * * argv)
 
         auto argPtrs = stringsToCharPtrs(args);
 
-        restoreAffinity();
         restoreSignals();
-        restoreMountNamespace();
 
         execvp(shell.c_str(), argPtrs.data());