sinelaw/fresh · warning · io::Error (InvalidData)

Could not parse MemTotal from /proc/meminfo

Error message

Could not parse MemTotal from /proc/meminfo

What it means

linux_total_memory_mb() parses /proc/meminfo looking for the MemTotal line, expecting a value in kB. If the file exists but no MemTotal entry can be found/parsed (or the file is empty/malformed), it returns io::ErrorKind::InvalidData with this message, since memory size cannot be established for limit enforcement.

Solutions

  1. Verify /proc/meminfo contains a MemTotal line (cat /proc/meminfo | grep MemTotal)
  2. Unmask /proc/meminfo in the container (remove volume/bind mounts hiding it)
  3. Fall back to getrusage/sysinfo(2) syscall or the sysinfo crate if procfs is unavailable
  4. Treat the error as non-fatal and skip memory limiting

Example fix

// before
let mem = total_memory_mb()?;
// after
let mem = total_memory_mb().unwrap_or_else(|e| {
    log::warn!("memory detect failed: {e}; skipping limits");
    u64::MAX
});
Defensive patterns

Strategy: fallback

Validate before calling

let meminfo = std::fs::read_to_string("/proc/meminfo")?;
let ok = meminfo.lines().any(|l| l.starts_with("MemTotal:"));
if !ok { /* skip limits or use fallback */ }

Try / catch

match total_memory_mb() { Ok(mb) => apply_limit(mb), Err(e) if e.kind() == io::ErrorKind::InvalidData => log::warn!("procfs unreadable: {e}"), Err(e) => return Err(e.into()), }

Prevention

When it happens

Trigger: Calling total_memory_mb() on Linux when /proc/meminfo lacks a parseable 'MemTotal: <n> kB' line — e.g. exotic kernels, restricted containers with masked /proc/meminfo, or locale/number formatting anomalies in the file.

Common situations: Running inside a container where /proc is remounted or partially masked; non-standard embedded Linux without full procfs; security hardening that hides meminfo fields.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

AI-assisted analysis of sinelaw/fresh@67894ca546 (2026-09-13). Data as JSON: /api/errors/5ad8870e4cd27b47. Report an issue: GitHub.

Appendix: source

Thrown at crates/fresh-editor-core/src/process_limits.rs:342

    #[cfg(target_os = "linux")]
    fn linux_total_memory_mb() -> io::Result<u64> {
        // Read from /proc/meminfo
        let meminfo = std::fs::read_to_string("/proc/meminfo")?;

        for line in meminfo.lines() {
            if line.starts_with("MemTotal:") {
                // Format: "MemTotal:       16384000 kB"
                let parts: Vec<&str> = line.split_whitespace().collect();
                if parts.len() >= 2 {
                    if let Ok(kb) = parts[1].parse::<u64>() {
                        return Ok(kb / 1024); // Convert KB to MB
                    }
                }
            }
        }

        Err(io::Error::new(
            io::ErrorKind::InvalidData,
            "Could not parse MemTotal from /proc/meminfo",
        ))
    }

    /// Get total number of CPU cores
    pub fn cpu_count() -> io::Result<usize> {
        #[cfg(target_os = "linux")]
        {
            Ok(num_cpus())
        }

        #[cfg(not(target_os = "linux"))]
        {
            // TODO: Implement for other platforms
            Err(io::Error::new(
                io::ErrorKind::Unsupported,
                "CPU detection not implemented for this platform",

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