tools/memory-model/litmus-tests/MP+onceassign+derefonce.litmus

File Facts

System

Linux kernel

Corpus path

tools/memory-model/litmus-tests/MP+onceassign+derefonce.litmus

Extension

.litmus

Size

593 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 rcu_assign_pointer

Annotated Snippet

C MP+onceassign+derefonce

(*
 * Result: Never
 *
 * This litmus test demonstrates that rcu_assign_pointer() and
 * rcu_dereference() suffice to ensure that an RCU reader will not see
 * pre-initialization garbage when it traverses an RCU-protected data
 * structure containing a newly inserted element.
 *)

{
p=y;
}

P0(int *x, int **p) // Producer
{
	WRITE_ONCE(*x, 1);
	rcu_assign_pointer(*p, x);
}

P1(int *x, int **p) // Consumer
{
	int *r0;
	int r1;

	rcu_read_lock();
	r0 = rcu_dereference(*p);
	r1 = READ_ONCE(*r0);
	rcu_read_unlock();
}

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

Annotation

• Detected declarations: `function rcu_assign_pointer`.
• 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.