Empty For Spin

ID

go.empty_for_spin

Severity

high

Remediation Complexity

trivial

Remediation Risk

low

Remediation Effort

low

Resource

Efficiency

Language

Go

Tags

efficiency, suspicious

Description

Reports a bare for {} loop — a for with no clause, no condition and an empty body. The loop has nothing to evaluate and nothing to do, so it spins as fast as the scheduler allows.

Rationale

An empty infinite loop pins a CPU core at 100% and starves other goroutines of scheduler time without making any progress. It is almost always a placeholder that should block on a channel receive, sleep, or run real work guarded by a loop condition. Loops with a condition (for cond {}) or a clause (for i := 0; …​; i++ {}) are not reported even with an empty body — they make progress or terminate.

for {} // FLAW — busy-spins, pinning a core

for { // OK — blocks on a channel
    select {
    case <-done:
        return
    }
}

Remediation

Block on a channel receive, add a time.Sleep, or give the loop a real condition so it makes progress or yields the processor.

References