commit 3748054cfed4305087a3cffdf03c264912ed10b0
author Nikita Ioffe <ioffe@google.com> Wed Feb 26 15:18:56 2020 +0000
committer Nikita Ioffe <ioffe@google.com> Fri Feb 28 11:40:10 2020 +0000
tree b85735e6b6b2dc859b44d0e79ac5ded47c21ef11
parent 96d9929c7fb80467488d258ef5f7cc0ca958f1a5

If userspace reboot watchdog triggers, don't store reason in persistent property

If init is wedged, then the write will never succeed and reboot won't
happen.

Also, in case of normal reboot, move call to PersistRebootReason to the
top of DoReboot() function, to make sure we persist it even if /data is
not mounted.

Test: builds
Test: adb shell svc power reboot userspace
Test: atest CtsUserspaceRebootHostSideTestCases
Bug: 148767783
Change-Id: I4ae40e1f6fdc41cc0bcae57020fa3d3385dda1b4
Merged-In: I4ae40e1f6fdc41cc0bcae57020fa3d3385dda1b4

init/reboot.cpp

diff --git a/init/reboot.cpp b/init/reboot.cpp
index 048c1e7..08b99ab 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -96,8 +96,10 @@
     return ret;
 }
 
-static void PersistRebootReason(const char* reason) {
-    SetProperty(LAST_REBOOT_REASON_PROPERTY, reason);
+static void PersistRebootReason(const char* reason, bool write_to_property) {
+    if (write_to_property) {
+        SetProperty(LAST_REBOOT_REASON_PROPERTY, reason);
+    }
     WriteStringToFile(reason, LAST_REBOOT_REASON_FILE);
 }
 
@@ -535,14 +537,6 @@
     Timer t;
     LOG(INFO) << "Reboot start, reason: " << reason << ", reboot_target: " << reboot_target;
 
-    // If /data isn't mounted then we can skip the extra reboot steps below, since we don't need to
-    // worry about unmounting it.
-    if (!IsDataMounted()) {
-        sync();
-        RebootSystem(cmd, reboot_target);
-        abort();
-    }
-
     // Ensure last reboot reason is reduced to canonical
     // alias reported in bootloader or system boot reason.
     size_t skip = 0;
@@ -552,9 +546,17 @@
          reasons[1] == "hard" || reasons[1] == "warm")) {
         skip = strlen("reboot,");
     }
-    PersistRebootReason(reason.c_str() + skip);
+    PersistRebootReason(reason.c_str() + skip, true);
     sync();
 
+    // If /data isn't mounted then we can skip the extra reboot steps below, since we don't need to
+    // worry about unmounting it.
+    if (!IsDataMounted()) {
+        sync();
+        RebootSystem(cmd, reboot_target);
+        abort();
+    }
+
     bool is_thermal_shutdown = cmd == ANDROID_RB_THERMOFF;
 
     auto shutdown_timeout = 0ms;
@@ -833,7 +835,8 @@
     if (!WaitForProperty("sys.boot_completed", "1", timeout)) {
         LOG(ERROR) << "Failed to boot in " << timeout.count() << "ms. Switching to full reboot";
         // In this case device is in a boot loop. Only way to recover is to do dirty reboot.
-        PersistRebootReason("userspace_failed,watchdog_triggered");
+        // Since init might be wedged, don't try to write reboot reason into a persistent property.
+        PersistRebootReason("userspace_failed,watchdog_triggered", false);
         RebootSystem(ANDROID_RB_RESTART2, "userspace_failed,watchdog_triggered");
     }
     LOG(INFO) << "Device booted, stopping userspace reboot watchdog";