rustup default stable command ends with "killed" after installing rustc

Verification

• I searched for recent similar issues at https://github.com/rust-lang/rustup/issues?q=is%3Aissue+is%3Aopen%2Cclosed and found no duplicates.
• I am on the latest version of Rustup according to https://github.com/rust-lang/rustup/tags and am still able to reproduce my issue.

Problem

Rustup Bug Report Summary

Issue Description

When attempting to set the default Rust toolchain using rustup default stable, the process fails with the error message "killed". This occurs on a fresh Ubuntu 22.04.5 LTS installation on AWS Lightsail.

Error Message

rustup default stable
info: using existing install for 'stable-x86_64-unknown-linux-gnu'
info: syncing channel updates for 'stable-x86_64-unknown-linux-gnu'
info: latest update on 2025-03-18, rust version 1.85.1 (4eb161250 2025-03-15)
info: downloading component 'rustc'
info: downloading component 'cargo'
info: downloading component 'rust-std'
info: downloading component 'rust-docs'
info: downloading component 'rustfmt'
info: downloading component 'clippy'
info: removing previous version of component 'rustc'
warn: during uninstall component rustc was not found
info: removing previous version of component 'cargo'
warn: during uninstall component cargo was not found
info: removing previous version of component 'rust-std'
warn: during uninstall component rust-std was not found
info: removing previous version of component 'rust-docs'
warn: during uninstall component rust-docs was not found
info: removing previous version of component 'rustfmt'
warn: during uninstall component rustfmt was not found
info: removing previous version of component 'clippy'
warn: during uninstall component clippy was not found
info: installing component 'rustc'
                                                         Killed

Steps

Steps to Reproduce

1. Installed rustup using the standard curl script: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
2. Selected option 1 (default installation)
3. Ran source "$HOME/.cargo/env" to configure the environment
4. Attempted to set default toolchain with rustup default stable

Possible Solution(s)

No response

Notes

• The installation appears to download components but fails during configuration
• No Rust executables are functional after installation (cargo and rustc commands fail)

...
error: Missing manifest in toolchain 'stable-x86_64-unknown-linux-gnu'```
- The error persists across multiple installation attempts and system reboots
- The system had a previous apt-installed version of Rust that was removed before installing rustup 

### Rustup version

```console
rustup --version
rustup 1.28.1 (f9edccde0 2025-03-05)
info: This is the version for the rustup toolchain manager, not the rustc compiler.
info: The currently active `rustc` version is `(error reading rustc version)`

Installed toolchains

rustup show
Default host: x86_64-unknown-linux-gnu
rustup home:  /home/ubuntu/.rustup

installed toolchains
--------------------
stable-x86_64-unknown-linux-gnu (active, default)

active toolchain
----------------
name: stable-x86_64-unknown-linux-gnu
active because: it's the default toolchain
installed targets:

OS version

## System Information
- OS: Ubuntu 22.04.5 LTS
- Architecture: x86_64
- Kernel: Linux 6.8.0-1024-aws
- Environment: AWS Lightsail instance

Start by reproducing rustup default stable on the reported Ubuntu 22.04.5 AWS Lightsail environment and review the installation log, especially the Killed result while installing rustc. Compare the behavior with the reported rustup version and installed toolchains; done means the default stable toolchain installs successfully and cargo and rustc work.