[PATCH] timekeeping: Refresh auxiliary base before offset validation

[PATCH] timekeeping: Refresh auxiliary base before offset validation

[Avi Weiss]

timekeeping_forward_now() can advance an auxiliary timekeeper across a
second boundary without refreshing tkr_mono.base. The negative-time
check in __timekeeping_inject_offset() then uses the stale base and
rejects valid ADJ_SETOFFSET adjustments with -EINVAL.

Refresh the derived timekeeper data before calculating the current
auxiliary time, as aux_clock_set() already does.

On 7.4-rc1, a valid negative adjustment fails at the first second
rollover. The patched kernel accepts all 12 tested rollover adjustments
and continues to reject invalid negative offsets.

Fixes: 2c8aea59c206 ("timekeeping: Add auxiliary clock support to __timekeeping_inject_offset()")
Signed-off-by: Avi Weiss <thnkslprpt@gmail.com>
---
 kernel/time/timekeeping.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index dcf47f1ffdcf..6d55cecf86ee 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1775,6 +1775,7 @@ static int __timekeeping_inject_offset(struct tk_data *tkd, const struct timespe
 		struct tk_read_base *tkr_mono = &tks->tkr_mono;
 		ktime_t now, offs;
 
+		tk_update_ktime_data(tks);
 		/* Get the current time */
 		now = ktime_add_ns(tkr_mono->base, timekeeping_get_ns(tkr_mono));
 		/* Add the relative offset change */

base-commit: 6628e7d4c6b25c8d18f1345e3a20d21829aae7e4
-- 
2.53.0