5.4-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Peterson benjamin@engflow.com
[ 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@engflow.com Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Tested-by: Howard Chu howardchu95@gmail.com Cc: Adrian Hunter adrian.hunter@intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Ian Rogers irogers@google.com Cc: Ingo Molnar mingo@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: Kan Liang kan.liang@linux.intel.com Cc: Mark Rutland mark.rutland@arm.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Link: https://lore.kernel.org/r/20241107232128.108981-2-benjamin@engflow.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 745ea920eca98..c8c01e706118e 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -2079,6 +2079,7 @@ 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; @@ -2094,8 +2095,8 @@ 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);