diff --git a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp
--- a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp
+++ b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp
@@ -353,7 +353,6 @@
   const lldb::addr_t file_end = address_range->data.GetRangeEnd();
   size_t bytes_to_read = size; // Number of bytes to read from the core file
   size_t bytes_copied = 0;   // Number of bytes actually read from the core file
-  size_t zero_fill_size = 0; // Padding
   lldb::addr_t bytes_left =
       0; // Number of bytes available in the core file from the given address
 
@@ -367,24 +366,15 @@
   if (file_end > file_start + offset)
     bytes_left = file_end - (file_start + offset);
 
-  // Figure out how many bytes we need to zero-fill if we are reading more
-  // bytes than available in the on-disk segment
-  if (bytes_to_read > bytes_left) {
-    zero_fill_size = bytes_to_read - bytes_left;
+  if (bytes_to_read > bytes_left)
     bytes_to_read = bytes_left;
-  }
 
   // If there is data available on the core file read it
   if (bytes_to_read)
     bytes_copied =
         core_objfile->CopyData(offset + file_start, bytes_to_read, buf);
 
-  assert(zero_fill_size <= size);
-  // Pad remaining bytes
-  if (zero_fill_size)
-    memset(((char *)buf) + bytes_copied, 0, zero_fill_size);
-
-  return bytes_copied + zero_fill_size;
+  return bytes_copied;
 }
 
 void ProcessElfCore::Clear() {
diff --git a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
--- a/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
+++ b/lldb/test/API/functionalities/postmortem/elf-core/TestLinuxCore.py
@@ -155,6 +155,24 @@
         self.do_test("linux-x86_64", self._x86_64_pid, self._x86_64_regions,
                      "a.out")
 
+
+    @skipIf(triple='^mips')
+    @skipIfLLVMTargetMissing("X86")
+    @skipIfWindows
+    @skipIfReproducer
+    def test_read_memory(self):
+        """Test that we are able to read as many bytes as available"""
+        target = self.dbg.CreateTarget("linux-x86_64.out")
+        process = target.LoadCore("linux-x86_64.core")
+        self.assertTrue(process, PROCESS_IS_VALID)
+
+        error = lldb.SBError()
+        bytesread = process.ReadMemory(0x400ff0, 20, error)
+        
+        # read only 16 bytes without zero bytes filling
+        self.assertEqual(len(bytesread), 16)
+        self.dbg.DeleteTarget(target)
+
     @skipIf(triple='^mips')
     @skipIfLLVMTargetMissing("X86")
     def test_FPR_SSE(self):