Files
linux/kernel/time
Adrian Hunter fcf190c369 timekeeping: Make delta calculation overflow safe
Kernel timekeeping is designed to keep the change in cycles (since the last
timer interrupt) below max_cycles, which prevents multiplication overflow
when converting cycles to nanoseconds. However, if timer interrupts stop,
the calculation will eventually overflow.

Add protection against that. In timekeeping_cycles_to_ns() calculation,
check against max_cycles, falling back to a slower higher precision
calculation. In timekeeping_forward_now(), process delta in chunks of at
most max_cycles.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240325064023.2997-18-adrian.hunter@intel.com
2024-04-08 15:03:08 +02:00
..
2024-04-08 15:03:06 +02:00
2020-10-30 21:57:07 +01:00
2023-07-14 13:47:07 -06:00
2024-04-08 15:03:07 +02:00