[PATCH v6 08/26] perf trace: Stop at internal fields when walking syscall arguments

[Ian Rogers]

Since v6.19 syscall tracepoints may end with __data_loc char[] fields
holding user space strings, these aren't syscall arguments.
syscall__scnprintf_args() walks them anyway, printing the extra raw
syscall arguments at those indices under the internal field's name, and
trace__bpf_sys_enter_beauty_map() considers them when building the BPF
beauty map. The internal fields come after the arguments, so stop at the
first one.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/builtin-trace.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 1ffe824ba670..35d39a3fe803 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2647,6 +2647,9 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 
 		for (field = sc->args; field;
 		     field = field->next, ++arg.idx, bit <<= 1) {
+			if (is_internal_field(field))
+				break;
+
 			if (arg.mask & bit)
 				continue;
 
@@ -4134,6 +4137,9 @@ static int trace__bpf_sys_enter_beauty_map(struct trace *trace, int e_machine, i
 		return -1;
 
 	for (i = 0, field = sc->args; field; ++i, field = field->next) {
+		if (is_internal_field(field))
+			break;
+
 		// XXX We're only collecting pointer payloads _from_ user space
 		if (!sc->arg_fmt[i].from_user)
 			continue;
@@ -4188,6 +4194,8 @@ static int trace__bpf_sys_enter_beauty_map(struct trace *trace, int e_machine, i
 
 			/* find the size of the buffer that appears in pairs with buf */
 			for (j = 0, field_tmp = sc->args; field_tmp; ++j, field_tmp = field_tmp->next) {
+				if (is_internal_field(field_tmp))
+					break;
 				if (!(field_tmp->flags & TEP_FIELD_IS_POINTER) && /* only integers */
 				    (strstr(field_tmp->name, "count") ||
 				     strstr(field_tmp->name, "siz") ||  /* size, bufsiz */
-- 
2.56.0.rc1.315.gc6ed9934b7-goog