initrdscripts: fsuuidinit: use file based mutex to avoid race condition

As soon as the UUID is regenerated udev runs the correspondign rules. However, the rules expect the new UUID to be cached in a file, so there is a race condition between the creation of the file and the udev rule. This commit avoid the race condition by using a file mutex that the udev rule can wait on. Change-type: patch Signed-off-by: Alex Gonzalez <[email protected]>
balena-os · May 11, 2024 · 3f6a302 · 3f6a302
1 parent ef51b29
commit 3f6a302
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/meta-balena-common/recipes-core/initrdscripts/files/fsuuidsinit b/meta-balena-common/recipes-core/initrdscripts/files/fsuuidsinit
@@ -57,10 +57,14 @@ fsuuidsinit_run() {
     for dev in /dev/disk/by-state/resin-rootB /dev/disk/by-state/resin-state /dev/disk/by-state/resin-data /dev/disk/by-state/resin-rootA; do
         uuid="$(get_dev_uuid "${dev}")"
         fstype="$(get_dev_fstype "${dev}")"
+        if [ "${uuid}" = "$(get_cmdline_root_uuid)" ]; then
+            touch "/run/initramfs/bootparam_root.mux"
+        fi
         if regenerate_uuid "${dev}" "${fstype}"; then
-            if [ "${uuid}" = "$(get_cmdline_root_uuid)" ]; then
+            if [ -f "/run/initramfs/bootparam_root.mux" ]; then
                 bootparam_root="UUID=$(get_dev_uuid "${dev}")"
                 echo "${bootparam_root}" > /run/initramfs/bootparam_root
+                rm -f "/run/initramfs/bootparam_root.mux"
                 info "Using new root UUID: ${bootparam_root}"
             fi
         else