[Nix-dev] "invalid mode for dlopen()" (mixing master and stdenv-updates)

[James Cook]

Hi nix-dev,

My global nixos installation is on the master branch
(/nix/store/yq2wrw6r2rgr7sgf5fg4a7jhhscg8fpv-nixos-0.2pre4520_7e10bcb-3b5b1be).

I updated $HOME/.nix-profile to a commit from the stdenv-updates
branch (I tried commits fc82aa0 and face3a8).

When I run commands, I get this error message:
  ls: error while loading shared libraries: __vdso_time: invalid mode
for dlopen(): Invalid argument

What I find particularly interesting:
  $ which ls
  /run/current-system/sw/bin/ls
(so I'm still using ls from master).

Two questions:
- I am assuming this is caused by mixing branches, but is it worth
testing that fact (bringing my global system up to stdenv-updates)?
- Assuming it is, is this a known problem?  Why doesn't nix's purity
prevent this?

I haven't really looked into this, because I am guessing someone out
there knows the answer.

James