Camera: Fix deadlock caused by ordering of mStatusLock and mCameraStatesLock.
The following lock order exists in addListenerHelper:
mCameraStatesLock -> mStatusLock. In CameraDeviceClient::disconnect()
the previous lock ordering was mStatusLock->mCameraStates lock. Move the
collection of logical camera ids out to avoid holding mCameraStatesLock
and mStatus lock in CameraService::updateStatus.
Bug: 162192331
Test: Camera cts
Test: GCA (basic validity)
Change-Id: Ie5f9f924a77f7073264e9b7fce739c74c98fb57a
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>
diff --git a/services/camera/libcameraservice/CameraService.cpp b/services/camera/libcameraservice/CameraService.cpp
index af1e01d..24288d6 100644
--- a/services/camera/libcameraservice/CameraService.cpp
+++ b/services/camera/libcameraservice/CameraService.cpp
@@ -3751,9 +3751,14 @@
__FUNCTION__, cameraId.string());
return;
}
+
+ // Collect the logical cameras without holding mStatusLock in updateStatus
+ // as that can lead to a deadlock(b/162192331).
+ auto logicalCameraIds = getLogicalCameras(cameraId);
// Update the status for this camera state, then send the onStatusChangedCallbacks to each
// of the listeners with both the mStatusLock and mStatusListenerLock held
- state->updateStatus(status, cameraId, rejectSourceStates, [this, &deviceKind, &supportsHAL3]
+ state->updateStatus(status, cameraId, rejectSourceStates, [this, &deviceKind, &supportsHAL3,
+ &logicalCameraIds]
(const String8& cameraId, StatusInternal status) {
if (status != StatusInternal::ENUMERATING) {
@@ -3773,8 +3778,8 @@
}
Mutex::Autolock lock(mStatusListenerLock);
-
- notifyPhysicalCameraStatusLocked(mapToInterface(status), cameraId, deviceKind);
+ notifyPhysicalCameraStatusLocked(mapToInterface(status), String16(cameraId),
+ logicalCameraIds, deviceKind);
for (auto& listener : mListenerList) {
bool isVendorListener = listener->isVendorListener();
@@ -3892,8 +3897,9 @@
return OK;
}
-void CameraService::notifyPhysicalCameraStatusLocked(int32_t status, const String8& cameraId,
- SystemCameraKind deviceKind) {
+std::list<String16> CameraService::getLogicalCameras(
+ const String8& physicalCameraId) {
+ std::list<String16> retList;
Mutex::Autolock lock(mCameraStatesLock);
for (const auto& state : mCameraStates) {
std::vector<std::string> physicalCameraIds;
@@ -3901,26 +3907,39 @@
// This is not a logical multi-camera.
continue;
}
- if (std::find(physicalCameraIds.begin(), physicalCameraIds.end(), cameraId.c_str())
+ if (std::find(physicalCameraIds.begin(), physicalCameraIds.end(), physicalCameraId.c_str())
== physicalCameraIds.end()) {
// cameraId is not a physical camera of this logical multi-camera.
continue;
}
- String16 id16(state.first), physicalId16(cameraId);
+ retList.emplace_back(String16(state.first));
+ }
+ return retList;
+}
+
+void CameraService::notifyPhysicalCameraStatusLocked(int32_t status,
+ const String16& physicalCameraId, const std::list<String16>& logicalCameraIds,
+ SystemCameraKind deviceKind) {
+ // mStatusListenerLock is expected to be locked
+ for (const auto& logicalCameraId : logicalCameraIds) {
for (auto& listener : mListenerList) {
+ // Note: we check only the deviceKind of the physical camera id
+ // since, logical camera ids and their physical camera ids are
+ // guaranteed to have the same system camera kind.
if (shouldSkipStatusUpdates(deviceKind, listener->isVendorListener(),
listener->getListenerPid(), listener->getListenerUid())) {
ALOGV("Skipping discovery callback for system-only camera device %s",
- cameraId.c_str());
+ String8(physicalCameraId).c_str());
continue;
}
listener->getListener()->onPhysicalCameraStatusChanged(status,
- id16, physicalId16);
+ logicalCameraId, physicalCameraId);
}
}
}
+
void CameraService::blockClientsForUid(uid_t uid) {
const auto clients = mActiveClientManager.getAll();
for (auto& current : clients) {
diff --git a/services/camera/libcameraservice/CameraService.h b/services/camera/libcameraservice/CameraService.h
index 4321201..685ed5e 100644
--- a/services/camera/libcameraservice/CameraService.h
+++ b/services/camera/libcameraservice/CameraService.h
@@ -49,6 +49,7 @@
#include <set>
#include <string>
+#include <list>
#include <map>
#include <memory>
#include <utility>
@@ -1005,8 +1006,13 @@
hardware::camera::common::V1_0::TorchModeStatus status);
// notify physical camera status when the physical camera is public.
- void notifyPhysicalCameraStatusLocked(int32_t status, const String8& cameraId,
- SystemCameraKind deviceKind);
+ // Expects mStatusListenerLock to be locked.
+ void notifyPhysicalCameraStatusLocked(int32_t status, const String16& physicalCameraId,
+ const std::list<String16>& logicalCameraIds, SystemCameraKind deviceKind);
+
+ // get list of logical cameras which are backed by physicalCameraId
+ std::list<String16> getLogicalCameras(const String8& physicalCameraId);
+
// IBinder::DeathRecipient implementation
virtual void binderDied(const wp<IBinder> &who);