5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Benjamin Peterson <benjamin@xxxxxxxxxxx> [ Upstream commit 1302e352b26f34991b619b5d0b621b76d20a3883 ] syscall__scnprintf_args may not place anything in the output buffer (e.g., because the arguments are all zero). If that happened in trace__fprintf_sys_enter, its fprintf would receive an unitialized buffer leading to garbage output. Fix the problem by passing the (possibly zero) bounds of the argument buffer to the output fprintf. Fixes: a98392bb1e169a04 ("perf trace: Use beautifiers on syscalls:sys_enter_ handlers") Signed-off-by: Benjamin Peterson <benjamin@xxxxxxxxxxx> Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Tested-by: Howard Chu <howardchu95@xxxxxxxxx> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> Cc: Ian Rogers <irogers@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20241107232128.108981-2-benjamin@xxxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/perf/builtin-trace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 49a968bdd3a27..65f94597590ef 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -2379,6 +2379,7 @@ static int trace__fprintf_sys_enter(struct trace *trace, struct evsel *evsel, char msg[1024]; void *args, *augmented_args = NULL; int augmented_args_size; + size_t printed = 0; if (sc == NULL) return -1; @@ -2394,8 +2395,8 @@ static int trace__fprintf_sys_enter(struct trace *trace, struct evsel *evsel, args = perf_evsel__sc_tp_ptr(evsel, args, sample); augmented_args = syscall__augmented_args(sc, sample, &augmented_args_size, trace->raw_augmented_syscalls_args_size); - syscall__scnprintf_args(sc, msg, sizeof(msg), args, augmented_args, augmented_args_size, trace, thread); - fprintf(trace->output, "%s", msg); + printed += syscall__scnprintf_args(sc, msg, sizeof(msg), args, augmented_args, augmented_args_size, trace, thread); + fprintf(trace->output, "%.*s", (int)printed, msg); err = 0; out_put: thread__put(thread); -- 2.43.0