diff --git a/services/audioflinger/FastCapture.cpp b/services/audioflinger/FastCapture.cpp
index 79ac12b..1bba5f6 100644
--- a/services/audioflinger/FastCapture.cpp
+++ b/services/audioflinger/FastCapture.cpp
@@ -131,7 +131,9 @@
             // FIXME new may block for unbounded time at internal mutex of the heap
             //       implementation; it would be better to have normal capture thread allocate for
             //       us to avoid blocking here and to prevent possible priority inversion
-            (void)posix_memalign(&mReadBuffer, 32, frameCount * Format_frameSize(mFormat));
+            size_t bufferSize = frameCount * Format_frameSize(mFormat);
+            (void)posix_memalign(&mReadBuffer, 32, bufferSize);
+            memset(mReadBuffer, 0, bufferSize); // if posix_memalign fails, will segv here.
             mPeriodNs = (frameCount * 1000000000LL) / mSampleRate;      // 1.00
             mUnderrunNs = (frameCount * 1750000000LL) / mSampleRate;    // 1.75
             mOverrunNs = (frameCount * 500000000LL) / mSampleRate;      // 0.50