Commit 948ac6d7 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds

[PATCH] clocksource: Fix thinko in watchdog selection

The watchdog implementation excludes low res / non continuous
clocksources from being selected as a watchdog reference
unintentionally.

Allow using jiffies/PIT as a watchdog reference as long as no better
clocksource is available. This is necessary to detect TSC breakage on
systems, which have no pmtimer/hpet.

The main goal of the initial patch (preventing to switch to highres/nohz
when no reliable fallback clocksource is available) is still guaranteed
by the checks in clocksource_watchdog().
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9501b6cf
...@@ -151,7 +151,8 @@ static void clocksource_check_watchdog(struct clocksource *cs) ...@@ -151,7 +151,8 @@ static void clocksource_check_watchdog(struct clocksource *cs)
watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL; watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
add_timer(&watchdog_timer); add_timer(&watchdog_timer);
} }
} else if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) { } else {
if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
if (!watchdog || cs->rating > watchdog->rating) { if (!watchdog || cs->rating > watchdog->rating) {
......
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