From: Fleuria <fleuria@posteo.co>
Date: Thu, 3 Apr 2025 13:18:38 +0000 (+0700)
Subject: timer: Do not recalculate monotonic elapse time on clock change
X-Git-Tag: v258-rc1~239
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bed9d2587c852c6dad5b2959a6313c8590e5d6a6;p=thirdparty%2Fsystemd.git

timer: Do not recalculate monotonic elapse time on clock change

The only clock change that affects monotonic timers is suspend causing
CLOCK_MONOTONIC to fall behind CLOCK_BOOTTIME. However, monotonic timers
that use CLOCK_BOOTTIME are not intended to have their elapse time
changed after a suspend. Hence condition the calculation of monotonic
timers’ elapse times on the cause not being a clock change.

Fixes #29245
---

diff --git a/src/core/timer.c b/src/core/timer.c
index e283a97983f..a45e0c393fe 100644
--- a/src/core/timer.c
+++ b/src/core/timer.c
@@ -486,7 +486,8 @@ static void timer_enter_waiting(Timer *t, bool time_change) {
                                 assert_not_reached();
                         }
 
-                        v->next_elapse = usec_add(usec_shift_clock(base, CLOCK_MONOTONIC, TIMER_MONOTONIC_CLOCK(t)), v->value);
+                        if (!time_change)
+                                v->next_elapse = usec_add(usec_shift_clock(base, CLOCK_MONOTONIC, TIMER_MONOTONIC_CLOCK(t)), v->value);
 
                         if (dual_timestamp_is_set(&t->last_trigger) &&
                             !time_change &&