[PATCH v5 1/3] tracing: Use __free() for expr_str() buffer
From: Pengpeng Hou <hidden>
Date: 2026-06-11 05:59:54
Also in:
lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
expr_str() allocates a temporary expression buffer and manually frees it on some error paths. Convert the buffer to __free(kfree) and return it with return_ptr() on success. This keeps ownership handling separate from the later ERR_PTR() conversion and string-bound change. Signed-off-by: Pengpeng Hou <redacted> --- kernel/trace/trace_events_hist.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 82ce492ab268..f778f060e922 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c@@ -1759,7 +1759,7 @@ static void expr_field_str(struct hist_field *field, char *expr) static char *expr_str(struct hist_field *field, unsigned int level) { - char *expr; + char *expr __free(kfree) = NULL; if (level > 1) return NULL;
@@ -1770,7 +1770,7 @@ static char *expr_str(struct hist_field *field, unsigned int level) if (!field->operands[0]) { expr_field_str(field, expr); - return expr; + return_ptr(expr); } if (field->operator == FIELD_OP_UNARY_MINUS) {
@@ -1778,16 +1778,15 @@ static char *expr_str(struct hist_field *field, unsigned int level) strcat(expr, "-("); subexpr = expr_str(field->operands[0], ++level); - if (!subexpr) { - kfree(expr); + if (!subexpr) return NULL; - } + strcat(expr, subexpr); strcat(expr, ")"); kfree(subexpr); - return expr; + return_ptr(expr); } expr_field_str(field->operands[0], expr);
@@ -1806,13 +1805,12 @@ static char *expr_str(struct hist_field *field, unsigned int level) strcat(expr, "*"); break; default: - kfree(expr); return NULL; } expr_field_str(field->operands[1], expr); - return expr; + return_ptr(expr); } /*
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2.50.1 (Apple Git-155)