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authorMichael Petlan <mpetlan@redhat.com>2021-03-02 15:41:20 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2021-03-06 16:54:32 -0300
commit86a19008af5d88d5d523dbfe9b6ede11473e9a7f (patch)
tree66faab23b448d9a37bc4b90d433d8076c13b8cb1
parent77d02bd00cea9f1a87afe58113fa75b983d6c23a (diff)
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>
-rw-r--r--tools/perf/builtin-trace.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 85b6a46e85b6..7ec18ff57fc4 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3964,9 +3964,6 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
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 @@ int cmd_trace(int argc, const char **argv)
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();