[code sync] Merge code from sonic-net/sonic-buildimage:202511 to 202512 (#2175)

```<br>* b174c71 - (HEAD -> 202512) Merge branch '202511' of https://github.com/sonic-net/sonic-buildimage into 202512 (2026-04-14) [Sonic Automation]
* 66766f5 - (head/202511) [rsyslog] Fix Trixie restart delay with conditional restart (#26576) (2026-04-14) [mssonicbld]
* 8b612d2 - Revert "[platform/broadcom]: Remove static warmboot mount from docker-syncd-b…" (#26730) (2026-04-13) [Liping Xu]<br>```

Author: mssonicbld

files/image_config/rsyslog/rsyslog-config.sh

@@ -40,8 +40,34 @@ if [ -z "$syslog_counter" ]; then
     syslog_counter="false"
 fi
 
+# Generate config to a temp file so we can compare before restarting.
+# On Debian 13 (Trixie), rsyslog.service has systemd sandboxing directives
+# (PrivateTmp, ProtectSystem, etc.) that add ~4 seconds of overhead per
+# restart due to namespace setup/teardown.  Skipping the restart when the
+# config is unchanged avoids this delay on warm/fast reboot and config_reload
+# where nothing actually changed.
+#
+# When the config IS unchanged we still send SIGHUP so rsyslog re-opens its
+# log files (needed after log rotation or /var/log remounts).
+#
+# See: https://github.com/sonic-net/sonic-buildimage/issues/25382
+
+TMPFILE=$(mktemp /tmp/rsyslog.conf.XXXXXX)
+trap 'rm -f "$TMPFILE"' EXIT
+
 sonic-cfggen -d -t /usr/share/sonic/templates/rsyslog.conf.j2 \
     -a "{\"udp_server_ip\": \"$udp_server_ip\", \"hostname\": \"$hostname\", \"docker0_ip\": \"$docker0_ip\", \"forward_with_osversion\": \"$syslog_with_osversion\", \"os_version\": \"$os_version\", \"syslog_counter\": \"$syslog_counter\"}" \
-    > /etc/rsyslog.conf
+    > "$TMPFILE"
 
-systemctl restart rsyslog
+if [ ! -f /etc/rsyslog.conf ] || ! cmp -s "$TMPFILE" /etc/rsyslog.conf; then
+    # Config changed (or first boot) — install and restart
+    if cp "$TMPFILE" /etc/rsyslog.conf; then
+        systemctl restart rsyslog
+    else
+        echo "Failed to update /etc/rsyslog.conf; not restarting rsyslog" >&2
+        exit 1
+    fi
+else
+    # Config unchanged — just signal rsyslog to re-open log files
+    systemctl kill -s HUP rsyslog
+fi

platform/broadcom/docker-syncd-brcm-legacy-th-rpc.mk

@@ -22,6 +22,7 @@ $(DOCKER_SYNCD_BRCM_LEGACY_TH_RPC)_VERSION = 1.0.0+rpc
 $(DOCKER_SYNCD_BRCM_LEGACY_TH_RPC)_PACKAGE_NAME = syncd-legacy-th
 $(DOCKER_SYNCD_BRCM_LEGACY_TH_RPC)_RUN_OPT += --privileged -t
 $(DOCKER_SYNCD_BRCM_LEGACY_TH_RPC)_RUN_OPT += -v /host/machine.conf:/etc/machine.conf
+$(DOCKER_SYNCD_BRCM_LEGACY_TH_RPC)_RUN_OPT += -v /host/warmboot:/var/warmboot
 $(DOCKER_SYNCD_BRCM_LEGACY_TH_RPC)_RUN_OPT += -v /var/run/docker-syncd:/var/run/sswsyncd
 $(DOCKER_SYNCD_BRCM_LEGACY_TH_RPC)_RUN_OPT += -v /etc/sonic:/etc/sonic:ro
 

platform/broadcom/docker-syncd-brcm-legacy-th.mk

@@ -42,6 +42,7 @@ $(DOCKER_SYNCD_LEGACY_TH_BASE)_CONTAINER_NAME = syncd
 $(DOCKER_SYNCD_LEGACY_TH_BASE)_RUN_OPT += --privileged -t
 $(DOCKER_SYNCD_LEGACY_TH_BASE)_RUN_OPT += -v /host/machine.conf:/etc/machine.conf
 $(DOCKER_SYNCD_LEGACY_TH_BASE)_RUN_OPT += -v /etc/sonic:/etc/sonic:ro
+$(DOCKER_SYNCD_LEGACY_TH_BASE)_RUN_OPT += -v /host/warmboot:/var/warmboot
 
 $(DOCKER_SYNCD_LEGACY_TH_BASE)_BASE_IMAGE_FILES += bcmcmd:/usr/bin/bcmcmd
 $(DOCKER_SYNCD_LEGACY_TH_BASE)_BASE_IMAGE_FILES += bcmsh:/usr/bin/bcmsh