This is a note to let you know that I've just added the patch titled
perf trace: Avoid garbage when not printing a syscall's arguments
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-trace-avoid-garbage-when-not-printing-a-syscall.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7d6f4db120a860c6c04870d126746c6aa8e34954
Author: Benjamin Peterson <benjamin@xxxxxxxxxxx>
Date: Thu Nov 7 23:21:27 2024 +0000
perf trace: Avoid garbage when not printing a syscall's arguments
[ 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>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index af8480ec53136..3ecd6868be2d6 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2414,6 +2414,7 @@ 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;
@@ -2429,8 +2430,8 @@ 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);
