test(generate): lock in rseq family and return classification

Audit of the rseq(2) syscall confirmed the existing classification is
correct and consistent with its siblings:

- KindNull: the rseq argument is a userspace struct pointer (not an fd or
  filesystem path), and args[2] flags are intentionally not captured, in
  line with the KindNull convention shared with set_robust_list and
  membarrier. (Already covered by classify_test.go.)
- FamilyMisc: rseq is not in the explicit family table and falls through
  to Misc, grouped with its closest per-thread sibling
  set_robust_list/get_robust_list (also Misc).
- Return value is int 0/-1 with no byte count, so its exit stays
  UNCLASSIFIED.

Add lock-in tests for the family and return-value classification (kind
was already covered) so a future drift in either is caught.

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

2 files changed, 15 insertions, 0 deletions

diff --git a/internal/generate/family_test.go b/internal/generate/family_test.go
index e2d80b8..a708090 100644
--- a/internal/generate/family_test.go
+++ b/internal/generate/family_test.go
@@ -41,6 +41,17 @@ func TestClassifySyscallFamily(t *testing.T) {
 		{"sys_enter_ioperm", FamilyMisc},
 		{"sys_enter_iopl", FamilyMisc},
 		{"sys_enter_modify_ldt", FamilyMisc},
+		// rseq(2) registers/unregisters a per-thread restartable-sequences area
+		// (a userspace struct pointer, not an fd/path). It is not in the explicit
+		// family table and intentionally falls through to Misc, sharing the family
+		// with its closest per-thread sibling set_robust_list/get_robust_list
+		// (also Misc). set_tid_address is Process, but rseq is grouped with the
+		// robust-list pair rather than the tid-address syscall; keep this in sync
+		// with the Misc list in docs/syscall-tracing-plan.md.
+		{"sys_enter_rseq", FamilyMisc},
+		{"sys_exit_rseq", FamilyMisc},
+		{"sys_enter_set_robust_list", FamilyMisc},
+		{"sys_enter_get_robust_list", FamilyMisc},
 		{"sys_enter_unlisted_future_syscall", FamilyMisc},
 	}
 
diff --git a/internal/generate/retclassify_test.go b/internal/generate/retclassify_test.go
index 1bbde51..3adae6e 100644
--- a/internal/generate/retclassify_test.go
+++ b/internal/generate/retclassify_test.go
@@ -47,6 +47,10 @@ func TestClassifyRetUnclassified(t *testing.T) {
 		// gettimeofday(2) returns int 0/-1 (no byte count); its exit carries a
 		// plain ret_event and must stay UNCLASSIFIED, not a read/write transfer.
 		"gettimeofday",
+		// rseq(2) returns int 0/-1 on (un)registration of the restartable-
+		// sequences area; it transfers no bytes, so its exit must stay
+		// UNCLASSIFIED (plain ret_event), like its KindNull siblings.
+		"rseq",
 	}
 	for _, name := range unclassified {
 		if got := ClassifyRet("sys_exit_" + name); got != Unclassified {