From 01db7fbf5487505b887fbd6a03c51f2adc952196 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Thu, 21 Sep 2017 13:46:01 -0600 Subject: [PATCH] selftests: timers: set-timer-lat: fix hang when std out/err are redirected do_timer_oneshot() uses select() as a timer with FD_SETSIZE and readfs is cleared with FD_ZERO without FD_SET. When stdout and stderr are redirected, the test hangs in select forever. Fix the problem calling select() with readfds empty and nfds zero. This is sufficient for using select() for timer. With this fix "./set-timer-lat > /dev/null 2>&1" no longer hangs. Signed-off-by: Shuah Khan Acked-by: Greg Hackmann Signed-off-by: Shuah Khan --- tools/testing/selftests/timers/set-timer-lat.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/tools/testing/selftests/timers/set-timer-lat.c b/tools/testing/selftests/timers/set-timer-lat.c index 9c92b7bd5641..ea1af5dbc7b6 100644 --- a/tools/testing/selftests/timers/set-timer-lat.c +++ b/tools/testing/selftests/timers/set-timer-lat.c @@ -228,7 +228,6 @@ int do_timer_oneshot(int clock_id, int flags) timer_t tm1; const int interval = 0; struct timeval timeout; - fd_set fds; int err; err = setup_timer(clock_id, flags, interval, &tm1); @@ -237,9 +236,8 @@ int do_timer_oneshot(int clock_id, int flags) memset(&timeout, 0, sizeof(timeout)); timeout.tv_sec = 5; - FD_ZERO(&fds); do { - err = select(FD_SETSIZE, &fds, NULL, NULL, &timeout); + err = select(0, NULL, NULL, NULL, &timeout); } while (err == -1 && errno == EINTR); timer_delete(tm1); -- 2.20.1