test(generate): lock in set_mempolicy_home_node classification

Audit of the set_mempolicy_home_node(2) NUMA syscall (task mz) confirmed
it is correctly classified: KindNull (name-only, ior does not capture the
addr/len range), FamilyMemory (matching its siblings set_mempolicy, mbind,
migrate_pages, move_pages and docs/syscall-tracing-plan.md), and an
Unclassified return (0/-1 with no byte count).

Add lock-in tests so the classification cannot silently drift:
- family_test.go asserts FamilyMemory for set_mempolicy_home_node and its
  NUMA siblings, with a note that get_mempolicy is the lone sibling still
  on FamilySecurity (tracked separately, out of scope here).
- retclassify_test.go asserts the exit stays UNCLASSIFIED.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2 files changed, 19 insertions, 0 deletions

diff --git a/internal/generate/family_test.go b/internal/generate/family_test.go
index 08a601a..61718af 100644
--- a/internal/generate/family_test.go
+++ b/internal/generate/family_test.go
@@ -19,6 +19,20 @@ func TestClassifySyscallFamily(t *testing.T) {
 		// FamilyIPC (where the pidfd_* lifecycle syscalls live).
 		{"sys_enter_process_madvise", FamilyMemory},
 		{"sys_exit_process_madvise", FamilyMemory},
+		// set_mempolicy_home_node(2) (Linux 5.17+) sets the home NUMA node for a
+		// memory range (start,len,home_node,flags); it returns 0/-1 with no byte
+		// count, so it is KindNull and Unclassified. It is a NUMA memory-policy
+		// syscall and shares FamilyMemory with its siblings set_mempolicy(2),
+		// mbind(2), migrate_pages(2), and move_pages(2). NOTE: get_mempolicy(2) is
+		// the one NUMA sibling currently classified FamilySecurity instead of
+		// FamilyMemory — that inconsistency is tracked separately and is out of
+		// scope for this set_mempolicy_home_node assertion.
+		{"sys_enter_set_mempolicy_home_node", FamilyMemory},
+		{"sys_exit_set_mempolicy_home_node", FamilyMemory},
+		{"sys_enter_set_mempolicy", FamilyMemory},
+		{"sys_enter_mbind", FamilyMemory},
+		{"sys_enter_migrate_pages", FamilyMemory},
+		{"sys_enter_move_pages", FamilyMemory},
 		{"sys_enter_execve", FamilyProcess},
 		{"sys_enter_rt_sigaction", FamilySignals},
 		{"sys_enter_clock_gettime", FamilyTime},
diff --git a/internal/generate/retclassify_test.go b/internal/generate/retclassify_test.go
index 3adae6e..70ade1a 100644
--- a/internal/generate/retclassify_test.go
+++ b/internal/generate/retclassify_test.go
@@ -51,6 +51,11 @@ func TestClassifyRetUnclassified(t *testing.T) {
 		// sequences area; it transfers no bytes, so its exit must stay
 		// UNCLASSIFIED (plain ret_event), like its KindNull siblings.
 		"rseq",
+		// set_mempolicy_home_node(2) sets the home NUMA node for a memory range
+		// and returns int 0/-1 (no byte count), so its exit carries a plain
+		// ret_event and must stay UNCLASSIFIED, like its NUMA siblings
+		// set_mempolicy/mbind/migrate_pages/move_pages.
+		"set_mempolicy_home_node",
 	}
 	for _, name := range unclassified {
 		if got := ClassifyRet("sys_exit_" + name); got != Unclassified {