Reboot sequence: Unmount active apexes before unmounting /data
Having mounted apexes with loop back devices backing files on /data
partition will prevent clean unmount of it. Unmounting them and tearing
down loop devices should minimize the risk of that.
Note that it won't fix the issue completely, as there are a few (~2-3)
processes that keep restarting even after SIGKILL is sent. Which means
that they can still hold references to apexes on /data partition. But
in practice probability of this is quite low.
Test: adb reboot
Test: put tzdata apex in /data/apex/active && adb reboot
Bug: 158152940
Change-Id: I4624567b3d0f304dba4c6e37b77abd89e57411de
diff --git a/init/reboot.cpp b/init/reboot.cpp
index e758fb3..2db0889 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -548,6 +548,18 @@
return still_running;
}
+static Result<void> UnmountAllApexes() {
+ const char* args[] = {"/system/bin/apexd", "--unmount-all"};
+ int status;
+ if (logwrap_fork_execvp(arraysize(args), args, &status, false, LOG_KLOG, true, nullptr) != 0) {
+ return ErrnoError() << "Failed to call '/system/bin/apexd --unmount-all'";
+ }
+ if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
+ return {};
+ }
+ return Error() << "'/system/bin/apexd --unmount-all' failed : " << status;
+}
+
//* Reboot / shutdown the system.
// cmd ANDROID_RB_* as defined in android_reboot.h
// reason Reason string like "reboot", "shutdown,userrequested"
@@ -704,6 +716,11 @@
// 5. drop caches and disable zram backing device, if exist
KillZramBackingDevice();
+ LOG(INFO) << "Ready to unmount apexes. So far shutdown sequence took " << t;
+ // 6. unmount active apexes, otherwise they might prevent clean unmount of /data.
+ if (auto ret = UnmountAllApexes(); !ret.ok()) {
+ LOG(ERROR) << ret.error();
+ }
UmountStat stat =
TryUmountAndFsck(cmd, run_fsck, shutdown_timeout - t.duration(), &reboot_semaphore);
// Follow what linux shutdown is doing: one more sync with little bit delay
@@ -742,18 +759,6 @@
StartSendingMessages();
}
-static Result<void> UnmountAllApexes() {
- const char* args[] = {"/system/bin/apexd", "--unmount-all"};
- int status;
- if (logwrap_fork_execvp(arraysize(args), args, &status, false, LOG_KLOG, true, nullptr) != 0) {
- return ErrnoError() << "Failed to call '/system/bin/apexd --unmount-all'";
- }
- if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
- return {};
- }
- return Error() << "'/system/bin/apexd --unmount-all' failed : " << status;
-}
-
static std::chrono::milliseconds GetMillisProperty(const std::string& name,
std::chrono::milliseconds default_value) {
auto value = GetUintProperty(name, static_cast<uint64_t>(default_value.count()));