Re: [PATCH] perf trace: Fix race in signal handling
From: Arnaldo Carvalho de Melo <acme@kernel.org>
Date: 2021-03-05 17:17:00
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Em Tue, Mar 02, 2021 at 03:41:20PM +0100, Michael Petlan escreveu:
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.Thanks, applied. - Arnaldo
quoted hunk ↗ jump to hunk
Suggested-by: Jiri Olsa <redacted> Signed-off-by: Michael Petlan <redacted> Tested-by: Michael Petlan <redacted> --- tools/perf/builtin-trace.c | 5 ++--- 1 file 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();-- 2.18.4
-- - Arnaldo