From: Yang Yingliang <[email protected]>
Check the delta of now and last to make sure it's not
negative while the clocksource mask is not 64-bits.
Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Yang Yingliang <[email protected]>
---
kernel/time/timekeeping_internal.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/time/timekeeping_internal.h
b/kernel/time/timekeeping_internal.h
index 4ea005a..cbfcd2d 100644
--- a/kernel/time/timekeeping_internal.h
+++ b/kernel/time/timekeeping_internal.h
@@ -16,8 +16,9 @@ extern void tk_debug_account_sleep_time(struct
timespec64 *t);
static inline cycle_t clocksource_delta(cycle_t now, cycle_t last,
cycle_t mask)
{
cycle_t ret = (now - last) & mask;
+ cycle_t negative = ret & ~(mask >> 1);
- return (s64) ret > 0 ? ret : 0;
+ return negative ? 0 : ret;
}
#else
static inline cycle_t clocksource_delta(cycle_t now, cycle_t last,
cycle_t mask)
--
2.5.0
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