diff --git a/compiler-rt/lib/gwp_asan/common.cpp b/compiler-rt/lib/gwp_asan/common.cpp
--- a/compiler-rt/lib/gwp_asan/common.cpp
+++ b/compiler-rt/lib/gwp_asan/common.cpp
@@ -59,6 +59,11 @@
   uintptr_t UncompressedBuffer[kMaxTraceLengthToCollect];
   size_t BacktraceLength =
       Backtrace(UncompressedBuffer, kMaxTraceLengthToCollect);
+  // Backtrace() returns the number of available frames, which may be greater
+  // than the number of frames in the buffer. In this case, we need to only pack
+  // the number of frames that are in the buffer.
+  if (BacktraceLength > kMaxTraceLengthToCollect)
+    BacktraceLength = kMaxTraceLengthToCollect;
   TraceSize =
       compression::pack(UncompressedBuffer, BacktraceLength, CompressedTrace,
                         AllocationMetadata::kStackFrameStorageBytes);
diff --git a/compiler-rt/lib/gwp_asan/tests/backtrace.cpp b/compiler-rt/lib/gwp_asan/tests/backtrace.cpp
--- a/compiler-rt/lib/gwp_asan/tests/backtrace.cpp
+++ b/compiler-rt/lib/gwp_asan/tests/backtrace.cpp
@@ -8,6 +8,7 @@
 
 #include <string>
 
+#include "gwp_asan/crash_handler.h"
 #include "gwp_asan/tests/harness.h"
 
 TEST_F(BacktraceGuardedPoolAllocator, DoubleFree) {
@@ -15,13 +16,13 @@
   GPA.deallocate(Ptr);
 
   std::string DeathRegex = "Double Free.*";
-  DeathRegex.append("backtrace\\.cpp:25.*");
+  DeathRegex.append("backtrace\\.cpp:26.*");
 
   DeathRegex.append("was deallocated.*");
-  DeathRegex.append("backtrace\\.cpp:15.*");
+  DeathRegex.append("backtrace\\.cpp:16.*");
 
   DeathRegex.append("was allocated.*");
-  DeathRegex.append("backtrace\\.cpp:14.*");
+  DeathRegex.append("backtrace\\.cpp:15.*");
   ASSERT_DEATH(GPA.deallocate(Ptr), DeathRegex);
 }
 
@@ -30,12 +31,36 @@
   GPA.deallocate(Ptr);
 
   std::string DeathRegex = "Use After Free.*";
-  DeathRegex.append("backtrace\\.cpp:40.*");
+  DeathRegex.append("backtrace\\.cpp:41.*");
 
   DeathRegex.append("was deallocated.*");
-  DeathRegex.append("backtrace\\.cpp:30.*");
+  DeathRegex.append("backtrace\\.cpp:31.*");
 
   DeathRegex.append("was allocated.*");
-  DeathRegex.append("backtrace\\.cpp:29.*");
+  DeathRegex.append("backtrace\\.cpp:30.*");
   ASSERT_DEATH({ *Ptr = 7; }, DeathRegex);
 }
+
+TEST(Backtrace, Short) {
+  gwp_asan::AllocationMetadata Meta;
+  Meta.AllocationTrace.RecordBacktrace(
+      [](uintptr_t *TraceBuffer, size_t /* Size */) -> size_t {
+        TraceBuffer[0] = 123u;
+        TraceBuffer[1] = 321u;
+        return 2u;
+      });
+  uintptr_t TraceOutput[2] = {};
+  EXPECT_EQ(2u, __gwp_asan_get_allocation_trace(&Meta, TraceOutput, 2));
+  EXPECT_EQ(TraceOutput[0], 123u);
+  EXPECT_EQ(TraceOutput[1], 321u);
+}
+
+TEST(Backtrace, ExceedsStorableLength) {
+  gwp_asan::AllocationMetadata Meta;
+  Meta.AllocationTrace.RecordBacktrace(
+      [](uintptr_t * /* TraceBuffer */, size_t /* Size */) -> size_t {
+        return SIZE_MAX; // Wow, that's big!
+      });
+  uintptr_t TraceOutput;
+  EXPECT_EQ(1u, __gwp_asan_get_allocation_trace(&Meta, &TraceOutput, 1));
+}