tools/memory-model/litmus-tests/MP+polockonce+poacquiresilsil.litmus

File Facts

System

Linux kernel

Corpus path

tools/memory-model/litmus-tests/MP+polockonce+poacquiresilsil.litmus

Extension

.litmus

Size

681 bytes

Lines

34

Domain

Support Tooling And Documentation

Bucket

tools

Inferred role

Support Tooling And Documentation: tools

Status

atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.

Dependency Surface

• No C-style include directives detected by the generator.

Detected Declarations

• function spin_is_locked

Annotated Snippet

C MP+polockonce+poacquiresilsil

(*
 * Result: Sometimes
 *
 * Do spinlocks provide order to outside observers using spin_is_locked()
 * to sense the lock-held state, ordered by acquire?  Note that when the
 * first spin_is_locked() returns false and the second true, we know that
 * the smp_load_acquire() executed before the lock was acquired (loosely
 * speaking).
 *)

{}

P0(spinlock_t *lo, int *x) // Producer
{
	spin_lock(lo);
	WRITE_ONCE(*x, 1);
	spin_unlock(lo);
}

P1(spinlock_t *lo, int *x) // Consumer
{
	int r1;
	int r2;
	int r3;

	r1 = smp_load_acquire(x);
	r2 = spin_is_locked(lo);
	r3 = spin_is_locked(lo);
}

exists (1:r1=1 /\ 1:r2=0 /\ 1:r3=1) (* Bad outcome. *)

Annotation

• Detected declarations: `function spin_is_locked`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: atlas-only.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.