--- /dev/null
+From ee85d3967ea09b215fcea5efdd90bbbf5e74a681 Mon Sep 17 00:00:00 2001
+From: Karel Zak <kzak@redhat.com>
+Date: Wed, 19 Feb 2020 15:50:47 +0100
+Subject: [PATCH] hwclock: fix for glibc 2.31 settimeofday()
+
+glibc announce:
+ ... settimeofday can no longer be used to set the time and the offset
+ simultaneously. If both of its two arguments are non-null, the call
+ will fail (setting errno to EINVAL).
+
+It means we need to call settimeofday(NULL, tz) and settimeofday(tv, NULL).
+
+Unfortunately, settimeofday(NULL, tz) has very special warp-clock
+semantic if used as the very first settimeofday() call. It means we
+have to be sure that we do not touch warp-clock if we need only need
+to modify system TZ. So, let's always call settimeofday(NULL, 0)
+before settimeofday(NULL, tz) for UTC rtc mode when modify system TZ.
+
+Upstream-Status: Backport [https://github.com/karelzak/util-linux/commit/ee85d3967ea09b215fcea5efdd90bbbf5e74a681]
+
+CC: J William Piggott <elseifthen@gmx.com>
+Signed-off-by: Karel Zak <kzak@redhat.com>
+Addresses: https://github.com/karelzak/util-linux/issues/957
+Signed-off-by: Liwei Song <liwei.song@windriver.com>
+---
+ sys-utils/hwclock.c | 49 ++++++++++++++++++++++++++-------------------
+ 1 file changed, 28 insertions(+), 21 deletions(-)
+
+diff --git a/sys-utils/hwclock.c b/sys-utils/hwclock.c
+index e736da7179f8..16576bc186ff 100644
+--- a/sys-utils/hwclock.c
++++ b/sys-utils/hwclock.c
+@@ -658,6 +658,9 @@ display_time(struct timeval hwctime)
+ * PCIL: persistent_clock_is_local, sets the "11 minute mode" timescale.
+ * firsttime: locks the warp_clock function (initialized to 1 at boot).
+ *
++ * Note that very first settimeofday(NULL, tz) modifies warp-clock as well as
++ * system TZ.
++ *
+ * +---------------------------------------------------------------------------+
+ * | op | RTC scale | settimeofday calls |
+ * |---------|-----------|-----------------------------------------------------|
+@@ -675,41 +678,45 @@ set_system_clock(const struct hwclock_control *ctl,
+ struct tm broken;
+ int minuteswest;
+ int rc = 0;
+- const struct timezone tz_utc = { 0 };
+
+ localtime_r(&newtime.tv_sec, &broken);
+ minuteswest = -get_gmtoff(&broken) / 60;
+
+ if (ctl->verbose) {
+- if (ctl->hctosys && !ctl->universal)
+- printf(_("Calling settimeofday(NULL, %d) to set "
+- "persistent_clock_is_local.\n"), minuteswest);
+- if (ctl->systz && ctl->universal)
++ if (ctl->universal)
+ puts(_("Calling settimeofday(NULL, 0) "
+- "to lock the warp function."));
++ "to lock the warp function."));
++ else
++ printf(_("Calling settimeofday(NULL, %d) to set "
++ "persistent_clock_is_local and "
++ "the kernel timezone.\n"), minuteswest);
++
++ if (ctl->universal && minuteswest)
++ printf(_("Calling settimeofday(NULL, %d) to set "
++ "the kernel timezone.\n"), minuteswest);
++
+ if (ctl->hctosys)
+- printf(_("Calling settimeofday(%ld.%06ld, %d)\n"),
+- newtime.tv_sec, newtime.tv_usec, minuteswest);
+- else {
+- printf(_("Calling settimeofday(NULL, %d) "), minuteswest);
+- if (ctl->universal)
+- puts(_("to set the kernel timezone."));
+- else
+- puts(_("to warp System time."));
+- }
++ printf(_("Calling settimeofday(%ld.%06ld, 0) to set "
++ "the kernel time.\n"), newtime.tv_sec, newtime.tv_usec);
+ }
+
+ if (!ctl->testing) {
++ const struct timezone tz_utc = { 0 };
+ const struct timezone tz = { minuteswest };
+
+- if (ctl->hctosys && !ctl->universal) /* set PCIL */
++ /* warp-clock */
++ if (ctl->universal)
++ rc = settimeofday(NULL, &tz_utc); /* lock to UTC */
++ else
++ rc = settimeofday(NULL, &tz); /* set PCIL and TZ */
++
++ /* set timezone */
++ if (!rc && ctl->universal && minuteswest)
+ rc = settimeofday(NULL, &tz);
+- if (ctl->systz && ctl->universal) /* lock warp_clock */
+- rc = settimeofday(NULL, &tz_utc);
++
++ /* set time */
+ if (!rc && ctl->hctosys)
+- rc = settimeofday(&newtime, &tz);
+- else if (!rc)
+- rc = settimeofday(NULL, &tz);
++ rc = settimeofday(&newtime, NULL);
+
+ if (rc) {
+ warn(_("settimeofday() failed"));
+--
+2.17.1
+
