tools/memory-model/litmus-tests/MP+unlocklockonceonce+fencermbonceonce.litmus

File Facts

System

Linux kernel

Corpus path

tools/memory-model/litmus-tests/MP+unlocklockonceonce+fencermbonceonce.litmus

Extension

.litmus

Size

564 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

• No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

C MP+unlocklockonceonce+fencermbonceonce

(*
 * Result: Never
 *
 * If two locked critical sections execute on the same CPU, stores in the
 * first must propagate to each CPU before stores in the second do, even if
 * the critical sections are protected by different locks.
 *)

{}

P0(spinlock_t *s, spinlock_t *t, int *x, int *y)
{
	spin_lock(s);
	WRITE_ONCE(*x, 1);
	spin_unlock(s);
	spin_lock(t);
	WRITE_ONCE(*y, 1);
	spin_unlock(t);
}

P1(int *x, int *y)
{
	int r1;
	int r2;

	r1 = READ_ONCE(*y);
	smp_rmb();
	r2 = READ_ONCE(*x);
}

exists (1:r1=1 /\ 1:r2=0)

Annotation

• 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.