"rustc" received signal SIGSEGV, Segmentation fault.

[haraldh]

Code

$ git clone https://github.com/enarx/enarx-keepldr
$ cd enarx-keepldr/internal/shim-sev
$ cargo build --release

error: could not compile `shim-sev`

Caused by:
  process didn't exit successfully: `rustc --crate-name shim_sev --edition=2018 src/main.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type bin --emit=dep-info,link -C opt-level=3 -C panic=abort -C lto -C codegen-units=1 -C debuginfo=1 -C metadata=93145a0a19b9eb83 -C extra-filename=-93145a0a19b9eb83 --out-dir /home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps --target x86_64-unknown-linux-musl -L dependency=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps -L dependency=/home/harald/enarx-keepldr/internal/shim-sev/target/release/deps --extern array_const_fn_init=/home/harald/enarx-keepldr/internal/shim-sev/target/release/deps/libarray_const_fn_init-905103751e9eb1a0.so --extern compiler_builtins=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libcompiler_builtins-651143acb5e6182c.rlib --extern crt0stack=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libcrt0stack-9bef3e32b96fe077.rlib --extern goblin=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libgoblin-de9034623bdae608.rlib --extern libc=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/liblibc-af38e4414248e0c7.rlib --extern lset=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/liblset-043238506a29c0f5.rlib --extern nbytes=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libnbytes-93811dbcb41a13d4.rlib --extern primordial=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libprimordial-e18cc863ec9a940f.rlib --extern rcrt1=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/librcrt1-632fb966fbd65d91.rlib --extern sallyport=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libsallyport-2aeba89cd68d5ac9.rlib --extern spinning=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libspinning-d441abb5ceb4336a.rlib --extern syscall=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libsyscall-9cd8f6736785a119.rlib --extern untrusted=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libuntrusted-5d7147986543cd15.rlib --extern x86_64=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/deps/libx86_64-2dc4159d46ccade0.rlib -C relocation-model=pic -C 'link-args=-Wl,--sort-section=alignment -nostartfiles' -C link-self-contained=no -C force-frame-pointers=yes -L native=/home/harald/enarx-keepldr/internal/shim-sev/target/x86_64-unknown-linux-musl/release/build/shim-sev-28519de2e5db2360/out -l static=asm` 

(signal: 11, SIGSEGV: invalid memory reference)

Meta

rustc --version --verbose:

rustc 1.50.0-nightly (a0d664bae 2020-11-22)
binary: rustc
commit-hash: a0d664bae6ca79c54cc054aa2403198e105190a2
commit-date: 2020-11-22
host: x86_64-unknown-linux-gnu
release: 1.50.0-nightly

Error output

gdb

Thread 6 "rustc" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffec97f640 (LWP 16168)]
0x00007ffff28a4f5a in llvm::X86TargetLowering::isZExtFree(llvm::SDValue, llvm::EVT) const ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
(gdb) bt
#0  0x00007ffff28a4f5a in llvm::X86TargetLowering::isZExtFree(llvm::SDValue, llvm::EVT) const ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#1  0x00007ffff0a1f317 in llvm::RegsForValue::getCopyToRegs(llvm::SDValue, llvm::SelectionDAG&, llvm::SDLoc const&, llvm::SDValue&, llvm::SDValue*, llvm::Value const*, llvm::ISD::NodeType) const ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#2  0x00007ffff0a4582d in llvm::SelectionDAGBuilder::visitInlineAsm(llvm::CallBase const&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#3  0x00007ffff0a22867 in llvm::SelectionDAGBuilder::visit(llvm::Instruction const&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#4  0x00007ffff0ae24fe in llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true>, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true>, bool&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#5  0x00007ffff0ae1b77 in llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#6  0x00007ffff0ade926 in llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#7  0x00007ffff27fda77 in (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#8  0x00007ffff064778e in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#9  0x00007ffff0421fd2 in llvm::FPPassManager::runOnFunction(llvm::Function&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#10 0x00007ffff04289e3 in llvm::FPPassManager::runOnModule(llvm::Module&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#11 0x00007ffff0422a2a in llvm::legacy::PassManagerImpl::run(llvm::Module&) ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/libLLVM-11-rust-1.50.0-nightly.so
#12 0x00007ffff4019130 in LLVMRustWriteOutputFile ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-4f0cc9f50e53f0ba.so
#13 0x00007ffff3f4d10c in rustc_codegen_llvm::back::write::write_output_file ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-4f0cc9f50e53f0ba.so
#14 0x00007ffff3f5192f in rustc_codegen_llvm::back::write::codegen ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-4f0cc9f50e53f0ba.so
#15 0x00007ffff3f32b6b in rustc_codegen_ssa::back::write::finish_intra_module_work ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-4f0cc9f50e53f0ba.so
#16 0x00007ffff3f2b937 in rustc_codegen_ssa::back::write::execute_work_item ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-4f0cc9f50e53f0ba.so
#17 0x00007ffff3e16ebf in std::sys_common::backtrace::__rust_begin_short_backtrace ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-4f0cc9f50e53f0ba.so
#18 0x00007ffff3e1ce4d in core::ops::function::FnOnce::call_once{{vtable-shim}} ()
   from /home/harald/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-4f0cc9f50e53f0ba.so
#19 0x00007ffff327ac6a in alloc::boxed::{{impl}}::call_once<(),FnOnce<()>,alloc::alloc::Global> ()
    at /rustc/a0d664bae6ca79c54cc054aa2403198e105190a2/library/alloc/src/boxed.rs:1318
#20 alloc::boxed::{{impl}}::call_once<(),alloc::boxed::Box<FnOnce<()>, alloc::alloc::Global>,alloc::alloc::Global> ()
    at /rustc/a0d664bae6ca79c54cc054aa2403198e105190a2/library/alloc/src/boxed.rs:1318
#21 std::sys::unix::thread::{{impl}}::new::thread_start () at library/std/src/sys/unix/thread.rs:71
#22 0x00007ffff319b3f9 in start_thread () from /lib64/libpthread.so.0
#23 0x00007ffff30b6903 in clone () from /lib64/libc.so.6

[haraldh]

It was this #[naked] (which was wrong anyway):

https://github.com/enarx/enarx-keepldr/blob/7eaf311424e6703a62bdd282baf6ac548a256006/internal/shim-sev/src/usermode.rs#L14