clockevents: prevent endless loop in tick_handle_periodic()

tick_handle_periodic() can lock up hard when a one shot clock event
device is used in combination with jiffies clocksource.

Avoid an endless loop issue by requiring that a highres valid
clocksource be installed before we call tick_periodic() in a loop when
using ONESHOT mode. The result is we will only increment jiffies once
per interrupt until a continuous hardware clocksource is available.

Without this, we can run into a endless loop, where each cycle through
the loop, jiffies is updated which increments time by tick_period or
more (due to clock steering), which can cause the event programming to
think the next event was before the newly incremented time and fail
causing tick_periodic() to be called again and the whole process loops
forever.

[ Impact: prevent hard lock up ]

Signed-off-by: John Stultz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]

0 files changed, 0 insertions, 0 deletions