From: David Engraf Date: Fri, 17 Feb 2017 07:51:03 +0000 (+0100) Subject: timers, sched_clock: Update timeout for clock wrap X-Git-Tag: v4.1.52~525 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2b24be15444aef66f1c8340b8300e37c8b2456e9;p=thirdparty%2Fkernel%2Fstable.git timers, sched_clock: Update timeout for clock wrap [ Upstream commit 1b8955bc5ac575009835e371ae55e7f3af2197a9 ] The scheduler clock framework may not use the correct timeout for the clock wrap. This happens when a new clock driver calls sched_clock_register() after the kernel called sched_clock_postinit(). In this case the clock wrap timeout is too long thus sched_clock_poll() is called too late and the clock already wrapped. On my ARM system the scheduler was no longer scheduling any other task than the idle task because the sched_clock() wrapped. Signed-off-by: David Engraf Signed-off-by: John Stultz Signed-off-by: Sasha Levin --- diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index a26036d37a389..382b159d8592e 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -205,6 +205,11 @@ sched_clock_register(u64 (*read)(void), int bits, unsigned long rate) update_clock_read_data(&rd); + if (sched_clock_timer.function != NULL) { + /* update timeout for clock wrap */ + hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL); + } + r = rate; if (r >= 4000000) { r /= 1000000;