Documentation/litmus-tests/atomic/cmpxchg-fail-unordered-1.litmus

File Facts

System

Linux kernel

Corpus path

Documentation/litmus-tests/atomic/cmpxchg-fail-unordered-1.litmus

Extension

.litmus

Size

498 bytes

Lines

35

Domain

Support Tooling And Documentation

Bucket

Documentation

Inferred role

Support Tooling And Documentation: Documentation

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 cmpxchg

Annotated Snippet

C cmpxchg-fail-unordered-1

(*
 * Result: Sometimes
 *
 * Demonstrate that a failing cmpxchg() operation does not act as a
 * full barrier.  (In contrast, a successful cmpxchg() does act as a
 * full barrier.)
 *)

{}

P0(int *x, int *y, int *z)
{
	int r0;
	int r1;

	WRITE_ONCE(*x, 1);
	r1 = cmpxchg(z, 1, 0);
	r0 = READ_ONCE(*y);
}

P1(int *x, int *y, int *z)
{
	int r0;
	int r1;

	WRITE_ONCE(*y, 1);
	r1 = cmpxchg(z, 1, 0);
	r0 = READ_ONCE(*x);
}

locations[0:r1;1:r1]
exists (0:r0=0 /\ 1:r0=0)

Annotation

• Detected declarations: `function cmpxchg`.
• Atlas domain: Support Tooling And Documentation / Documentation.
• 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.