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

File Facts

System

Linux kernel

Corpus path

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

Extension

.litmus

Size

545 bytes

Lines

31

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.

Dependency Surface

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

Detected Declarations

• function smp_wmb

Annotated Snippet

C MP+fencewmbonceonce+fencermbonceonce

(*
 * Result: Never
 *
 * This litmus test demonstrates that smp_wmb() and smp_rmb() provide
 * sufficient ordering for the message-passing pattern.  However, it
 * is usually better to use smp_store_release() and smp_load_acquire().
 *)

{}

P0(int *buf, int *flag) // Producer
{
	WRITE_ONCE(*buf, 1);
	smp_wmb();
	WRITE_ONCE(*flag, 1);
}

P1(int *buf, int *flag) // Consumer
{
	int r0;
	int r1;

	r0 = READ_ONCE(*flag);
	smp_rmb();
	r1 = READ_ONCE(*buf);
}

exists (1:r0=1 /\ 1:r1=0) (* Bad outcome. *)

Annotation

• Detected declarations: `function smp_wmb`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: atlas-only.

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.