tools/testing/selftests/bpf/progs/verifier_spin_lock.c

File Facts

System

Linux kernel

Corpus path

tools/testing/selftests/bpf/progs/verifier_spin_lock.c

Extension

.c

Size

12954 bytes

Lines

560

Domain

Support Tooling And Documentation

Bucket

tools

Inferred role

Support Tooling And Documentation: implementation source

Status

source implementation candidate

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.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/bpf.h
• bpf/bpf_helpers.h
• bpf_misc.h

Detected Declarations

• struct val
• function __msg_unpriv
• function __msg
• function __msg
• function __msg
• function __msg
• function __msg
• function __msg
• function __msg
• function __msg
• function __msg_unpriv
• function __attribute__
• function __msg
• function __msg
• function __msg
• function __msg_unpriv

Annotated Snippet

struct val {
	int cnt;
	struct bpf_spin_lock l;
};

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__uint(max_entries, 1);
	__type(key, int);
	__type(value, struct val);
} map_spin_lock SEC(".maps");

SEC("cgroup/skb")
__description("spin_lock: test1 success")
__success __failure_unpriv __msg_unpriv("")
__retval(0)
__naked void spin_lock_test1_success(void)
{
	asm volatile ("					\
	r1 = 0;						\
	*(u32*)(r10 - 4) = r1;				\
	r2 = r10;					\
	r2 += -4;					\
	r1 = %[map_spin_lock] ll;			\
	call %[bpf_map_lookup_elem];			\
	if r0 != 0 goto l0_%=;				\
	exit;						\
l0_%=:	r6 = r0;					\
	r1 = r0;					\
	r1 += 4;					\
	call %[bpf_spin_lock];				\
	r1 = r6;					\
	r1 += 4;					\
	r0 = *(u32*)(r6 + 0);				\
	call %[bpf_spin_unlock];			\
	r0 = 0;						\
	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm(bpf_spin_lock),
	  __imm(bpf_spin_unlock),
	  __imm_addr(map_spin_lock)
	: __clobber_all);
}

SEC("cgroup/skb")
__description("spin_lock: test2 direct ld/st")
__failure __msg("cannot be accessed directly")
__failure_unpriv __msg_unpriv("")
__naked void lock_test2_direct_ld_st(void)
{
	asm volatile ("					\
	r1 = 0;						\
	*(u32*)(r10 - 4) = r1;				\
	r2 = r10;					\
	r2 += -4;					\
	r1 = %[map_spin_lock] ll;			\
	call %[bpf_map_lookup_elem];			\
	if r0 != 0 goto l0_%=;				\
	exit;						\
l0_%=:	r6 = r0;					\
	r1 = r0;					\
	r1 += 4;					\
	call %[bpf_spin_lock];				\
	r1 = r6;					\
	r1 += 4;					\
	r0 = *(u32*)(r1 + 0);				\
	call %[bpf_spin_unlock];			\
	r0 = 0;						\
	exit;						\
"	:
	: __imm(bpf_map_lookup_elem),
	  __imm(bpf_spin_lock),
	  __imm(bpf_spin_unlock),
	  __imm_addr(map_spin_lock)
	: __clobber_all);
}

SEC("cgroup/skb")
__description("spin_lock: test3 direct ld/st")
__failure __msg("cannot be accessed directly")
__failure_unpriv __msg_unpriv("")
__flag(BPF_F_ANY_ALIGNMENT)
__naked void lock_test3_direct_ld_st(void)
{
	asm volatile ("					\
	r1 = 0;						\
	*(u32*)(r10 - 4) = r1;				\
	r2 = r10;					\
	r2 += -4;					\

Annotation

• Immediate include surface: `linux/bpf.h`, `bpf/bpf_helpers.h`, `bpf_misc.h`.
• Detected declarations: `struct val`, `function __msg_unpriv`, `function __msg`, `function __msg`, `function __msg`, `function __msg`, `function __msg`, `function __msg`, `function __msg`, `function __msg`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.
• 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.