diff --git a/msm8998/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp b/msm8998/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp
index 20eb1ade..22dbf65a 100644
--- a/msm8998/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp
+++ b/msm8998/mm-video-v4l2/vidc/venc/src/omx_video_base.cpp
@@ -2747,6 +2747,7 @@ OMX_ERRORTYPE  omx_video::use_output_buffer(
         return OMX_ErrorBadParameter;
     }
 
+    auto_lock l(m_buf_lock);
     if (!m_out_mem_ptr) {
         output_use_buffer = true;
         int nBufHdrSize        = 0;
@@ -3703,6 +3704,7 @@ OMX_ERRORTYPE  omx_video::free_buffer(OMX_IN OMX_HANDLETYPE         hComp,
                 nPortIndex, (unsigned int)m_sOutPortDef.nBufferCountActual);
         if (nPortIndex < m_sOutPortDef.nBufferCountActual &&
                 BITMASK_PRESENT(&m_out_bm_count, nPortIndex)) {
+            auto_lock l(m_buf_lock);
             // Clear the bit associated with it.
             BITMASK_CLEAR(&m_out_bm_count,nPortIndex);
             m_sOutPortDef.bPopulated = OMX_FALSE;