[PATCH] ntp: fix bug in adjtimex reading time offset
From: Dalmas, Marcelo (GE Vernova)
Date: Mon Nov 25 2024 - 08:05:11 EST
Due to an unsigned cast, adjtimex returns wrong offest when using ADJ_MICRO and the offset is negative.
In this case a small negative offset return approximately 4.29 seconds (~ 2^32/1000 milliseconds).
Signed-off-by: Marcelo Dalmas <marcelo.dalmas@xxxxxx>
---
kernel/time/ntp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index b550ebe0f03b..02e7fe6a0afa 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -798,7 +798,7 @@ int __do_adjtimex(struct __kernel_timex *txc, const struct timespec64 *ts,
txc->offset = shift_right(ntpdata->time_offset * NTP_INTERVAL_FREQ, NTP_SCALE_SHIFT);
if (!(ntpdata->time_status & STA_NANO))
- txc->offset = (u32)txc->offset / NSEC_PER_USEC;
+ txc->offset /= NSEC_PER_USEC;
}
result = ntpdata->time_state;
--
2.39.5