diff --git a/compiler-rt/lib/profile/InstrProfiling.h b/compiler-rt/lib/profile/InstrProfiling.h
--- a/compiler-rt/lib/profile/InstrProfiling.h
+++ b/compiler-rt/lib/profile/InstrProfiling.h
@@ -101,13 +101,13 @@
 /*!
  * \brief Merge profile data from buffer.
  *
- * Read profile data form buffer \p Profile  and merge with
- * in-process profile counters. The client is expected to
- * have checked or already knows the profile data in the
- * buffer matches the in-process counter structure before
- * calling it.
+ * Read profile data form buffer \p Profile  and merge with in-process profile
+ * counters. The client is expected to have checked or already knows the profile
+ * data in the buffer matches the in-process counter structure before calling
+ * it. Returns 0 (success) if the profile data is valid. Upon reading
+ * invalid/corrupted profile data, returns 1 (failure).
  */
-void __llvm_profile_merge_from_buffer(const char *Profile, uint64_t Size);
+int __llvm_profile_merge_from_buffer(const char *Profile, uint64_t Size);
 
 /*! \brief Check if profile in buffer matches the current binary.
  *
diff --git a/compiler-rt/lib/profile/InstrProfilingFile.c b/compiler-rt/lib/profile/InstrProfilingFile.c
--- a/compiler-rt/lib/profile/InstrProfilingFile.c
+++ b/compiler-rt/lib/profile/InstrProfilingFile.c
@@ -261,9 +261,15 @@
     return -1;
 
   /* Now start merging */
-  __llvm_profile_merge_from_buffer(ProfileBuffer, ProfileFileSize);
+  if (__llvm_profile_merge_from_buffer(ProfileBuffer, ProfileFileSize)) {
+    PROF_ERR("%s\n", "Invalid profile data to merge");
+    /* If the profile being merged is invalid, remove it entirely. */
+    (void)COMPILER_RT_FTRUNCATE(ProfileFile, 0);
+    (void)munmap(ProfileBuffer, ProfileFileSize);
+    return -1;
+  }
 
-  // Truncate the file in case merging of value profile did not happend to
+  // Truncate the file in case merging of value profile did not happen to
   // prevent from leaving garbage data at the end of the profile file.
   (void)COMPILER_RT_FTRUNCATE(ProfileFile,
                               __llvm_profile_get_size_for_buffer());
diff --git a/compiler-rt/lib/profile/InstrProfilingMerge.c b/compiler-rt/lib/profile/InstrProfilingMerge.c
--- a/compiler-rt/lib/profile/InstrProfilingMerge.c
+++ b/compiler-rt/lib/profile/InstrProfilingMerge.c
@@ -82,8 +82,8 @@
 }
 
 COMPILER_RT_VISIBILITY
-void __llvm_profile_merge_from_buffer(const char *ProfileData,
-                                      uint64_t ProfileSize) {
+int __llvm_profile_merge_from_buffer(const char *ProfileData,
+                                     uint64_t ProfileSize) {
   __llvm_profile_data *SrcDataStart, *SrcDataEnd, *SrcData, *DstData;
   __llvm_profile_header *Header = (__llvm_profile_header *)ProfileData;
   uint64_t *SrcCountersStart;
@@ -99,34 +99,46 @@
       (ValueProfData *)(SrcNameStart + Header->NamesSize +
                         __llvm_profile_get_num_padding_bytes(
                             Header->NamesSize));
+  size_t MaxNumCounters = ((uint64_t *)SrcNameStart) - SrcCountersStart;
+  if (MaxNumCounters < 0)
+    return 1;
 
   for (SrcData = SrcDataStart,
       DstData = (__llvm_profile_data *)__llvm_profile_begin_data(),
       SrcValueProfData = SrcValueProfDataStart;
        SrcData < SrcDataEnd; ++SrcData, ++DstData) {
-    uint64_t *SrcCounters;
     uint64_t *DstCounters = (uint64_t *)DstData->CounterPtr;
-    unsigned I, NC, NVK = 0;
+    unsigned NVK = 0;
 
-    NC = SrcData->NumCounters;
-    SrcCounters = SrcCountersStart +
-                  ((size_t)SrcData->CounterPtr - Header->CountersDelta) /
-                      sizeof(uint64_t);
-    for (I = 0; I < NC; I++)
+    unsigned NC = SrcData->NumCounters;
+    if (NC == 0 || NC > (unsigned)MaxNumCounters)
+      return 1;
+    size_t SrcCountersOffset =
+        ((size_t)SrcData->CounterPtr - Header->CountersDelta) /
+        sizeof(uint64_t);
+    if (SrcCountersOffset < 0 || SrcCountersOffset > MaxNumCounters ||
+        SrcCountersOffset + (size_t)NC > MaxNumCounters)
+      return 1;
+    uint64_t *SrcCounters = SrcCountersStart + SrcCountersOffset;
+    for (unsigned I = 0; I < NC; I++)
       DstCounters[I] += SrcCounters[I];
 
-    /* Now merge value profile data.  */
+    /* Now merge value profile data. */
     if (!VPMergeHook)
       continue;
 
-    for (I = 0; I <= IPVK_Last; I++)
+    for (unsigned I = 0; I <= IPVK_Last; I++)
       NVK += (SrcData->NumValueSites[I] != 0);
 
     if (!NVK)
       continue;
 
+    if (SrcValueProfData >= ProfileData + ProfileSize)
+      return 1;
     VPMergeHook(SrcValueProfData, DstData);
     SrcValueProfData = (ValueProfData *)((char *)SrcValueProfData +
                                          SrcValueProfData->TotalSize);
   }
+
+  return 0;
 }
diff --git a/compiler-rt/test/profile/Linux/instrprof-merge-vp.c b/compiler-rt/test/profile/Linux/instrprof-merge-vp.c
--- a/compiler-rt/test/profile/Linux/instrprof-merge-vp.c
+++ b/compiler-rt/test/profile/Linux/instrprof-merge-vp.c
@@ -14,7 +14,7 @@
 int __llvm_profile_runtime = 0;
 int __llvm_profile_write_file();
 void __llvm_profile_reset_counters(void);
-void __llvm_profile_merge_from_buffer(const char *, uint64_t);
+int __llvm_profile_merge_from_buffer(const char *, uint64_t);
 void __llvm_profile_set_filename(const char *);
 struct __llvm_profile_data;
 struct ValueProfData;
diff --git a/compiler-rt/test/profile/instrprof-merge.c b/compiler-rt/test/profile/instrprof-merge.c
--- a/compiler-rt/test/profile/instrprof-merge.c
+++ b/compiler-rt/test/profile/instrprof-merge.c
@@ -14,7 +14,7 @@
 uint64_t __llvm_profile_get_size_for_buffer(void);
 int __llvm_profile_write_buffer(char *);
 void __llvm_profile_reset_counters(void);
-void __llvm_profile_merge_from_buffer(const char *, uint64_t);
+int __llvm_profile_merge_from_buffer(const char *, uint64_t);
 
 int dumpBuffer(const char *FileN, const char *Buffer, uint64_t Size) {
   FILE *File = fopen(FileN, "w");
diff --git a/compiler-rt/test/profile/instrprof-without-libc.c b/compiler-rt/test/profile/instrprof-without-libc.c
--- a/compiler-rt/test/profile/instrprof-without-libc.c
+++ b/compiler-rt/test/profile/instrprof-without-libc.c
@@ -19,7 +19,7 @@
 int __llvm_profile_runtime = 0;
 uint64_t __llvm_profile_get_size_for_buffer(void);
 int __llvm_profile_write_buffer(char *);
-void __llvm_profile_merge_from_buffer(const char *, uint64_t Size);
+int __llvm_profile_merge_from_buffer(const char *, uint64_t Size);
 
 int write_buffer(uint64_t, const char *);
 int main(int argc, const char *argv[]) {