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[FP6] All 43 sensors unavailable due to SELinux label timing issue in init.target.rc

Device

  • Device: Fairphone 6 (FP6)
  • /e/OS version: 3.4-a15 (Android 15)
  • Build: BP1A.250505.005
  • Firmware: FP6.QREL.15.162.0

Problem

All 43 hardware sensors are unavailable on /e/OS a15 for FP6:

  • Accelerometer (ICM4x6xx) - not working
  • Gyroscope (ICM4x6xx) - not working
  • Magnetometer (QMC630x) - not working
  • Light sensor (STK3BCx) - not working
  • Proximity sensor (STK3BCx) - not working
  • Pressure sensor (SPL07) - not working
  • All fusion sensors (gravity, rotation vector, etc.) - not working

This means auto-rotate, adaptive brightness, compass, and proximity-based screen-off during calls are all broken.

Root Cause

SELinux file label timing issue in device/fairphone/FP6/init/init.target.rc.

The sensor directories are created by vendor init scripts (init.vendor.sensors.rc) during early-boot, but restorecon_recursive /mnt/vendor/persist runs earlier during on fs. Since the directories don't exist yet when restorecon runs, they get created later with wrong SELinux labels:

Path Expected Label Actual Label
/mnt/vendor/persist/sensors/ vendor_persist_sensors_file mnt_vendor_file
/data/vendor/sensors/ vendor_sensors_vendor_data_file vendor_data_file

This blocks sscrpcd (vendor_sensors) and sensors.qti (vendor_sensors_qti) from accessing their data directories, preventing all sensor initialization on the Qualcomm Sensor Core (SSC).

The Qcom vendor SELinux policy already has the correct file_contexts and allow rules — they just never get applied because the directories don't exist at restorecon time.

Fix

7-line change to init/init.target.rc. Create sensor directories before the existing restorecon_recursive call:

 on fs
     start hwservicemanager
     mount_all /vendor/etc/fstab.qcom --early
     chown root system /mnt/vendor/persist
     chmod 0771 /mnt/vendor/persist
+    mkdir /mnt/vendor/persist/sensors 0775 system system
+    mkdir /mnt/vendor/persist/sensors/registry 0775 system system
+    mkdir /mnt/vendor/persist/sensors/registry/registry 0775 system system
     restorecon_recursive /mnt/vendor/persist
     mkdir /mnt/vendor/persist/secnvm 0770 system system

 on post-fs-data
     mkdir /vendor/data/tombstones 0771 system system
+    # Sensor data directories
+    mkdir /data/vendor/sensors 0770 system system
+    mkdir /data/vendor/sensors/scripts 0770 system system
+    mkdir /data/vendor/sensors/diag_cfg 0770 system system
+    restorecon_recursive /data/vendor/sensors
     # Enable WLAN cold boot calibration
     write /sys/kernel/cnss/fs_ready 1

No sepolicy .te file changes needed.

Testing

  • Tested on FP6 with /e/OS 3.4-a15, SELinux enforcing
  • All 43 hardware sensors operational after reboot
  • Zero SELinux denials in dmesg
  • Auto-rotate, adaptive brightness, proximity all confirmed working
  • Accelerometer returning valid data (ICM4x6xx, 1-500Hz)

Verification Steps

To verify on a rooted device:

# Check current (wrong) labels
adb shell "su -c 'ls -Z /mnt/vendor/persist/sensors/'"
# Shows: mnt_vendor_file (WRONG)

# Fix labels
adb shell "su -c 'restorecon -Rv /mnt/vendor/persist/sensors/'"
adb shell "su -c 'restorecon -Rv /data/vendor/sensors/'"

# Restart sensors
adb shell "su -c 'stop vendor.sensors-hal-multihal && stop vendor.sensors && stop vendor.sensors.qti'"
adb shell "su -c 'start vendor.sensors && start vendor.sensors.qti && sleep 2 && start vendor.sensors-hal-multihal'"

# Verify
adb shell dumpsys sensorservice | head -3
# Should show: Total 43 h/w sensors
Edited by reinier de la parra