Commit 5fb8e565 authored by Benjamin Peterson's avatar Benjamin Peterson Committed by Namhyung Kim
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perf trace: avoid garbage when not printing a trace event's arguments 



trace__fprintf_tp_fields may not print any tracepoint arguments. E.g., if the
argument values are all zero. Previously, this would result in a totally
uninitialized buffer being passed to fprintf, which could lead to garbage on the
console. Fix the problem by passing the number of initialized bytes fprintf.

Fixes: f11b2803 ("perf trace: Allow choosing how to augment the tracepoint arguments")
Signed-off-by: default avatarBenjamin Peterson <benjamin@engflow.com>
Tested-by: default avatarHoward Chu <howardchu95@gmail.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20241103204816.7834-1-benjamin@engflow.com


Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent 29bf07bc

tools/perf/builtin-trace.c

+1 −1
Original line number Diff line number Diff line
@@ -3087,7 +3087,7 @@ static size_t trace__fprintf_tp_fields(struct trace *trace, struct evsel *evsel, 
		printed += syscall_arg_fmt__scnprintf_val(arg, bf + printed, size - printed, &syscall_arg, val);

	}



	return printed + fprintf(trace->output, "%s", bf);

	return printed + fprintf(trace->output, "%.*s", (int)printed, bf);

}



static int trace__event_handler(struct trace *trace, struct evsel *evsel,