Running -unstable in a single core VM with 2G RAM:
$ nixos-version
20.03pre196836.1c40ee6fc44 (Markhor)
$ grep MemTotal /proc/meminfo
MemTotal: 2041736 kB
The following steps led to the crash immediately after boot in complete
idle state:
# nix repl '<nixpkgs>'
Welcome to Nix version 2.3.1. Type :? for help.
Loading '<nixpkgs>'...
Added 10966 variables.
nix-repl> :l <nixpkgs/nixos>
Added 6 variables.
I then curiously looked through various variables by tab completing on
`config.` and eventually printing the following variables in the exact
order of listing; full output redacted for the sake of readability:
nix-repl> config.boot.kernelModules
nix-repl> config
nix-repl> config.fileSystems
nix-repl> config.zramSwap
nix-repl> config.system
nix-repl> config.environemnt
^C^P^C
^C
Segmentation fault (core dumped)
All variables were properly printed except the last one. Note how
"environemnt" was mistyped. "^C^P^C<Enter>^C<Enter>" was typed
literally as I noticed it hanging.
Backtrace:
#0 0x000000000049e37b in nix::EvalState::forceValue(nix::Value&, nix::Pos const&) ()
#1 0x00007fa4ca0887b4 in nix::ExprVar::eval(nix::EvalState&, nix::Env&, nix::Value&) ()
from /nix/store/cqzmhhibmhw5h92qwjd0ki4y4jhk0pl4-nix-2.3.1/lib/libnixexpr.so
#2 0x00007fa4ca089f1e in nix::ExprSelect::eval(nix::EvalState&, nix::Env&, nix::Value&) ()
from /nix/store/cqzmhhibmhw5h92qwjd0ki4y4jhk0pl4-nix-2.3.1/lib/libnixexpr.so
#3 0x00000000004e4a1b in nix::NixRepl::evalString(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, nix::Value&) ()
#4 0x00000000004e7760 in nix::NixRepl::processLine(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >) ()
#5 0x00000000004e7ce2 in nix::NixRepl::mainLoop(std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&) ()
#6 0x00000000004e965b in nix::CmdRepl::run(nix::ref<nix::Store>) ()
#7 0x00000000004b7449 in nix::StoreCommand::run() ()
#8 0x00000000004d57c8 in nix::mainWrapped(int, char**) ()
#9 0x00007fa4c9d8201c in nix::handleExceptions(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::function<void ()>)
()
from /nix/store/cqzmhhibmhw5h92qwjd0ki4y4jhk0pl4-nix-2.3.1/lib/libnixmain.so
#10 0x0000000000441fab in main ()
I saved both executable and core dump for later inspection, feel free
to ask for further details.
I cannot reproduce this issue.