commit c9ca6788c65ed3f578d1a1ed0ba7c268254dcb4b
author Shuzhen Wang <shuzhenwang@google.com> Tue Apr 26 13:40:31 2016 -0700
committer Shuzhen Wang <shuzhenwang@google.com> Tue Apr 26 14:18:53 2016 -0700
tree b7a4981b001064d8bb4870e4ab6dd6a923dcf124
parent 34713c04b5e1a897b0fd905a89622059a787f7a7

Camera: Use separate lock for mStreamingRequestId

There are cases where evictClientIdByRemote holds
mBinderSerializationLock and waits for mRequestLock, and at the same
time checkAndStopRepeatingRequest holds mRequestLock and waits for
mBinderSerializationLock, causing deadlock.

Solution is to use separate lock to protect mStreamingRequestId.

Bug: 28295136
Change-Id: I40f8e1ded29abde86bc12b20dd119f9f3371ebb2

services/camera/libcameraservice/api2/CameraDeviceClient.cpp

diff --git a/services/camera/libcameraservice/api2/CameraDeviceClient.cpp b/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
index 63e44fd..dbec34e 100644
--- a/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
+++ b/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
@@ -234,6 +234,7 @@
             res = STATUS_ERROR(CameraService::ERROR_INVALID_OPERATION,
                     msg.string());
         } else {
+            Mutex::Autolock idLock(mStreamingRequestIdLock);
             mStreamingRequestId = submitInfo->mRequestId;
         }
     } else {
@@ -271,6 +272,7 @@
         return STATUS_ERROR(CameraService::ERROR_DISCONNECTED, "Camera device no longer alive");
     }
 
+    Mutex::Autolock idLock(mStreamingRequestIdLock);
     if (mStreamingRequestId != requestId) {
         String8 msg = String8::format("Camera %d: Canceling request ID %d doesn't match "
                 "current request ID %d", mCameraId, requestId, mStreamingRequestId);
@@ -760,6 +762,7 @@
     }
 
     // FIXME: Also need check repeating burst.
+    Mutex::Autolock idLock(mStreamingRequestIdLock);
     if (mStreamingRequestId != REQUEST_ID_NONE) {
         String8 msg = String8::format(
             "Camera %d: Try to waitUntilIdle when there are active streaming requests",
@@ -792,6 +795,7 @@
         return STATUS_ERROR(CameraService::ERROR_DISCONNECTED, "Camera device no longer alive");
     }
 
+    Mutex::Autolock idLock(mStreamingRequestIdLock);
     mStreamingRequestId = REQUEST_ID_NONE;
     status_t err = mDevice->flush(lastFrameNumber);
     if (err != OK) {
@@ -982,7 +986,7 @@
         remoteCb->onRepeatingRequestError(lastFrameNumber);
     }
 
-    Mutex::Autolock icl(mBinderSerializationLock);
+    Mutex::Autolock idLock(mStreamingRequestIdLock);
     mStreamingRequestId = REQUEST_ID_NONE;
 }