perf trace: Fix race in signal handling
Since a lot of stuff happens before the SIGINT signal handler is registered
(scanning /proc/*, etc.), on bigger systems, such as Cavium Sabre CN99xx,
it may happen that first interrupt signal is lost and perf isn't correctly
terminated.
The reproduction code might look like the following:
perf trace -a &
PERF_PID=$!
sleep 4
kill -INT $PERF_PID
The issue has been found on a CN99xx machine with RHEL-8 and the patch fixes
it by registering the signal handlers earlier in the init stage.
Suggested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Tested-by: Michael Petlan <mpetlan@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/lkml/YEJnaMzH2ctp3PPx@kernel.org/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 85b6a46..7ec18ff 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3964,9 +3964,6 @@
evlist__config(evlist, &trace->opts, &callchain_param);
- signal(SIGCHLD, sig_handler);
- signal(SIGINT, sig_handler);
-
if (forks) {
err = evlist__prepare_workload(evlist, &trace->opts.target, argv, false, NULL);
if (err < 0) {
@@ -4827,6 +4824,8 @@
signal(SIGSEGV, sighandler_dump_stack);
signal(SIGFPE, sighandler_dump_stack);
+ signal(SIGCHLD, sig_handler);
+ signal(SIGINT, sig_handler);
trace.evlist = evlist__new();
trace.sctbl = syscalltbl__new();
