From 012749caf9419f22636891259b664c6dd383e897 Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Thu, 6 Jun 2019 10:38:59 -0300 Subject: [PATCH] perf trace: Exit when failing to build eBPF program On my Juno board with ARM64 CPUs, perf trace command reports the eBPF program building failure but the command will not exit and continue to run. If we define an eBPF event in config file, the event will be parsed with below flow: perf_config() `> trace__config() `> parse_events_option() `> parse_events__scanner() `-> parse_events_parse() `> parse_events_load_bpf() `> llvm__compile_bpf() Though the low level functions return back error values when detect eBPF building failure, but parse_events_option() returns 1 for this case and trace__config() passes 1 to perf_config(); perf_config() doesn't treat the returned value 1 as failure and it continues to parse other configurations. Thus the perf command continues to run even without enabling eBPF event successfully. This patch changes error handling in trace__config(), when it detects failure it will return -1 rather than directly pass error value (1); finally, perf_config() will directly bail out and perf will exit for this case. Committer notes: Simplified the patch to just check directly the return of parse_events_option() and it it is non-zero, change err from its initial zero value to -1. Signed-off-by: Leo Yan Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Jiri Olsa Cc: Martin KaFai Lau Cc: Mathieu Poirier Cc: Mike Leach Cc: Namhyung Kim Cc: Song Liu Cc: Suzuki Poulouse Cc: Yonghong Song Fixes: ac96287cae08 ("perf trace: Allow specifying a set of events to add in perfconfig") Link: https://lkml.kernel.org/n/tip-x4i63f5kscykfok0hqim3zma@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-trace.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index f7e4e50..1a2a605 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -3703,7 +3703,12 @@ static int trace__config(const char *var, const char *value, void *arg) struct option o = OPT_CALLBACK('e', "event", &trace->evlist, "event", "event selector. use 'perf list' to list available events", parse_events_option); - err = parse_events_option(&o, value, 0); + /* + * We can't propagate parse_event_option() return, as it is 1 + * for failure while perf_config() expects -1. + */ + if (parse_events_option(&o, value, 0)) + err = -1; } else if (!strcmp(var, "trace.show_timestamp")) { trace->show_tstamp = perf_config_bool(var, value); } else if (!strcmp(var, "trace.show_duration")) { -- 2.7.4