Workaround missing OnChannelClose for DisplayManagerService
After several doff/don cycles in a stress test, DisplayManagerService
eventually got into a state where it would not allow new connections
despite the old connection being long gone. We confirmed that it
had a display_manager_ pointer set when it should not have, which
means there was a missing OnChannelClose for probably some error
case that directly closed the channel without synthesizing the close.
Those cases should be fixed in followup CLs, but this change will
be helpful to guarantee Display Manager Service continues to operate
regardless. This service is uniquely sensitive to this bug.
Bug: 69004445
Test: Continuously doffed and donned with script
Change-Id: I46c47da38f1024b61dad0f6c19c64aeec53015a6
(cherry picked from commit 8dbbe5584b2fb9589fceed81333a0d5ff6c913a3)
diff --git a/libs/vr/libpdx/private/pdx/service.h b/libs/vr/libpdx/private/pdx/service.h
index 0d30614..13aa3e9 100644
--- a/libs/vr/libpdx/private/pdx/service.h
+++ b/libs/vr/libpdx/private/pdx/service.h
@@ -589,6 +589,14 @@
}
/*
+ * Return true if a channel with the given ID exists in the Channel map.
+ */
+ bool HasChannelId(int channel_id) const {
+ std::lock_guard<std::mutex> autolock(channels_mutex_);
+ return channels_.find(channel_id) != channels_.end();
+ }
+
+ /*
* Subclasses of Service may override this method to provide a text string
* describing the state of the service. This method is called by
* HandleSystemMessage in response to the standard
diff --git a/libs/vr/libvrflinger/display_manager_service.cpp b/libs/vr/libvrflinger/display_manager_service.cpp
index ef8cca3..34b3b0a 100644
--- a/libs/vr/libvrflinger/display_manager_service.cpp
+++ b/libs/vr/libvrflinger/display_manager_service.cpp
@@ -45,6 +45,14 @@
const int user_id = message.GetEffectiveUserId();
const bool trusted = user_id == AID_ROOT || IsTrustedUid(user_id);
+ // Check if the display_manager_ has a defunct channel.
+ if (display_manager_ && !HasChannelId(display_manager_->channel_id())) {
+ ALOGE("DisplayManagerService::OnChannelOpen: Found defunct channel %d with "
+ "no OnChannelClose, clearing prior display manager.",
+ display_manager_->channel_id());
+ display_manager_ = nullptr;
+ }
+
// Prevent more than one display manager from registering at a time or
// untrusted UIDs from connecting.
if (display_manager_ || !trusted) {