Handle possible overflow, implementation-defined result of signed right shift and replace unsuitable constant.
Signed-off-by: Andrey Drobyshev <[email protected]> Signed-off-by: Alexander GQ Gerasiov <[email protected]> --- kernel/time/ntp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 22f2235..9cef1b9 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -91,6 +91,7 @@ static time64_t ntp_next_leap_sec = TIME64_MAX; */ #define PPS_VALID 10 /* PPS signal watchdog max (s) */ #define PPS_POPCORN 4 /* popcorn spike threshold (shift) */ +#define PPS_JITUPD 2 /* pps_jitter update factor (shift) */ #define PPS_INTMIN 2 /* min freq interval (s) (shift) */ #define PPS_INTMAX 8 /* max freq interval (s) (shift) */ #define PPS_INTCOUNT 4 /* number of consecutive good intervals to @@ -941,7 +942,7 @@ static void hardpps_update_phase(long error) * threshold, the sample is discarded; otherwise, if so enabled, * the time offset is updated. */ - if (jitter > (pps_jitter << PPS_POPCORN)) { + if (pps_jitter && (jitter > ((long long)pps_jitter << PPS_POPCORN))) { printk_deferred(KERN_WARNING "hardpps: PPSJITTER: jitter=%ld, limit=%ld\n", jitter, (pps_jitter << PPS_POPCORN)); @@ -955,7 +956,7 @@ static void hardpps_update_phase(long error) time_adjust = 0; } /* update jitter */ - pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN; + pps_jitter += shift_right(jitter - pps_jitter, PPS_JITUPD); } /* -- 2.1.4
