diff --git a/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.rb b/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.rb
index da90b24f63e..63176d4ff74 100644
--- a/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.rb
+++ b/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.rb
@@ -80,7 +80,91 @@ def _nt_config
     r0
   end
 
+  module NewlineOrEoi0
+  end
+
+  def _nt_newline_or_eoi
+    start_index = index
+    if node_cache[:newline_or_eoi].has_key?(index)
+      cached = node_cache[:newline_or_eoi][index]
+      if cached
+        node_cache[:newline_or_eoi][index] = cached = SyntaxNode.new(input, index...(index + 1)) if cached == true
+        @index = cached.interval.end
+      end
+      return cached
+    end
+
+    i0 = index
+    i1, s1 = index, []
+    if (match_len = has_terminal?("\r", false, index))
+      r3 = true
+      @index += match_len
+    else
+      terminal_parse_failure('"\\r"')
+      r3 = nil
+    end
+    if r3
+      r2 = r3
+    else
+      r2 = instantiate_node(SyntaxNode,input, index...index)
+    end
+    s1 << r2
+    if r2
+      if (match_len = has_terminal?("\n", false, index))
+        r4 = true
+        @index += match_len
+      else
+        terminal_parse_failure('"\\n"')
+        r4 = nil
+      end
+      s1 << r4
+    end
+    if s1.last
+      r1 = instantiate_node(SyntaxNode,input, i1...index, s1)
+      r1.extend(NewlineOrEoi0)
+    else
+      @index = i1
+      r1 = nil
+    end
+    if r1
+      r1 = SyntaxNode.new(input, (index-1)...index) if r1 == true
+      r0 = r1
+    else
+      i5 = index
+      if index < input_length
+        r6 = true
+        @index += 1
+      else
+        terminal_parse_failure("any character")
+        r6 = nil
+      end
+      if r6
+        @index = i5
+        r5 = nil
+        terminal_parse_failure("any character", true)
+      else
+        @terminal_failures.pop
+        @index = i5
+        r5 = instantiate_node(SyntaxNode,input, index...index)
+      end
+      if r5
+        r5 = SyntaxNode.new(input, (index-1)...index) if r5 == true
+        r0 = r5
+      else
+        @index = i0
+        r0 = nil
+      end
+    end
+
+    node_cache[:newline_or_eoi][start_index] = r0
+
+    r0
+  end
+
   module Comment0
+    def newline_or_eoi
+      elements[3]
+    end
   end
 
   def _nt_comment
@@ -132,29 +216,8 @@ def _nt_comment
           r5 = instantiate_node(SyntaxNode,input, i5...index, s5)
           s1 << r5
           if r5
-            if (match_len = has_terminal?("\r", false, index))
-              r8 = true
-              @index += match_len
-            else
-              terminal_parse_failure('"\\r"')
-              r8 = nil
-            end
-            if r8
-              r7 = r8
-            else
-              r7 = instantiate_node(SyntaxNode,input, index...index)
-            end
+            r7 = _nt_newline_or_eoi
             s1 << r7
-            if r7
-              if (match_len = has_terminal?("\n", false, index))
-                r9 = true
-                @index += match_len
-              else
-                terminal_parse_failure('"\\n"')
-                r9 = nil
-              end
-              s1 << r9
-            end
           end
         end
       end
@@ -1674,7 +1737,7 @@ def _nt_hash
   end
 
   module Hashentries0
-    def whitespace
+    def cs
       elements[0]
     end
 
@@ -1708,7 +1771,7 @@ def _nt_hashentries
       s2, i2 = [], index
       loop do
         i3, s3 = index, []
-        r4 = _nt_whitespace
+        r4 = _nt_cs
         s3 << r4
         if r4
           r5 = _nt_hashentry
diff --git a/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.treetop b/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.treetop
index 9af43f608ea..d7af0af60fb 100644
--- a/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.treetop
+++ b/logstash-core/lib/logstash/compiler/lscl/lscl_grammar.treetop
@@ -6,8 +6,13 @@ grammar LogStashCompilerLSCLGrammar
     (cs plugin_section)* cs <LogStash::Compiler::LSCL::AST::Config>
   end
 
+  rule newline_or_eoi
+    # `!.` is a negative lookahead for 'anything', i.e. it matches at the end of input.
+    ("\r"? "\n") / !.
+  end
+
   rule comment
-    (whitespace? "#" [^\r\n]* "\r"? "\n")+ <LogStash::Compiler::LSCL::AST::Comment>
+    (whitespace? "#" [^\r\n]* newline_or_eoi)+ <LogStash::Compiler::LSCL::AST::Comment>
   end
 
   rule cs
@@ -114,7 +119,7 @@ grammar LogStashCompilerLSCLGrammar
   end
 
   rule hashentries
-    hashentry (whitespace hashentry)*
+    hashentry (cs hashentry)*
     <LogStash::Compiler::LSCL::AST::HashEntries>
   end
 
diff --git a/logstash-core/lib/logstash/config/grammar.rb b/logstash-core/lib/logstash/config/grammar.rb
index 008878c8ca6..e7de111e818 100644
--- a/logstash-core/lib/logstash/config/grammar.rb
+++ b/logstash-core/lib/logstash/config/grammar.rb
@@ -104,7 +104,91 @@ def _nt_config
     r0
   end
 
+  module NewlineOrEoi0
+  end
+
+  def _nt_newline_or_eoi
+    start_index = index
+    if node_cache[:newline_or_eoi].has_key?(index)
+      cached = node_cache[:newline_or_eoi][index]
+      if cached
+        node_cache[:newline_or_eoi][index] = cached = SyntaxNode.new(input, index...(index + 1)) if cached == true
+        @index = cached.interval.end
+      end
+      return cached
+    end
+
+    i0 = index
+    i1, s1 = index, []
+    if (match_len = has_terminal?("\r", false, index))
+      r3 = true
+      @index += match_len
+    else
+      terminal_parse_failure('"\\r"')
+      r3 = nil
+    end
+    if r3
+      r2 = r3
+    else
+      r2 = instantiate_node(SyntaxNode,input, index...index)
+    end
+    s1 << r2
+    if r2
+      if (match_len = has_terminal?("\n", false, index))
+        r4 = true
+        @index += match_len
+      else
+        terminal_parse_failure('"\\n"')
+        r4 = nil
+      end
+      s1 << r4
+    end
+    if s1.last
+      r1 = instantiate_node(SyntaxNode,input, i1...index, s1)
+      r1.extend(NewlineOrEoi0)
+    else
+      @index = i1
+      r1 = nil
+    end
+    if r1
+      r1 = SyntaxNode.new(input, (index-1)...index) if r1 == true
+      r0 = r1
+    else
+      i5 = index
+      if index < input_length
+        r6 = true
+        @index += 1
+      else
+        terminal_parse_failure("any character")
+        r6 = nil
+      end
+      if r6
+        @index = i5
+        r5 = nil
+        terminal_parse_failure("any character", true)
+      else
+        @terminal_failures.pop
+        @index = i5
+        r5 = instantiate_node(SyntaxNode,input, index...index)
+      end
+      if r5
+        r5 = SyntaxNode.new(input, (index-1)...index) if r5 == true
+        r0 = r5
+      else
+        @index = i0
+        r0 = nil
+      end
+    end
+
+    node_cache[:newline_or_eoi][start_index] = r0
+
+    r0
+  end
+
   module Comment0
+    def newline_or_eoi
+      elements[3]
+    end
   end
 
   def _nt_comment
@@ -156,29 +240,8 @@ def _nt_comment
           r5 = instantiate_node(SyntaxNode,input, i5...index, s5)
           s1 << r5
           if r5
-            if (match_len = has_terminal?("\r", false, index))
-              r8 = true
-              @index += match_len
-            else
-              terminal_parse_failure('"\\r"')
-              r8 = nil
-            end
-            if r8
-              r7 = r8
-            else
-              r7 = instantiate_node(SyntaxNode,input, index...index)
-            end
+            r7 = _nt_newline_or_eoi
             s1 << r7
-            if r7
-              if (match_len = has_terminal?("\n", false, index))
-                r9 = true
-                @index += match_len
-              else
-                terminal_parse_failure('"\\n"')
-                r9 = nil
-              end
-              s1 << r9
-            end
           end
         end
       end
@@ -1698,7 +1761,7 @@ def _nt_hash
   end
 
   module Hashentries0
-    def whitespace
+    def cs
       elements[0]
     end
 
@@ -1732,7 +1795,7 @@ def _nt_hashentries
       s2, i2 = [], index
       loop do
         i3, s3 = index, []
-        r4 = _nt_whitespace
+        r4 = _nt_cs
         s3 << r4
         if r4
           r5 = _nt_hashentry
diff --git a/logstash-core/lib/logstash/config/grammar.treetop b/logstash-core/lib/logstash/config/grammar.treetop
index 16dcd20b691..e0497c83244 100644
--- a/logstash-core/lib/logstash/config/grammar.treetop
+++ b/logstash-core/lib/logstash/config/grammar.treetop
@@ -6,8 +6,13 @@ grammar LogStashConfig
     cs plugin_section cs (cs plugin_section)* cs <LogStash::Config::AST::Config>
   end
 
+  rule newline_or_eoi
+    # `!.` is a negative lookahead for 'anything', i.e. it matches at the end of input.
+    ("\r"? "\n") / !.
+  end
+
   rule comment
-    (whitespace? "#" [^\r\n]* "\r"? "\n")+ <LogStash::Config::AST::Comment>
+    (whitespace? "#" [^\r\n]* newline_or_eoi)+ <LogStash::Config::AST::Comment>
   end
 
   rule cs
@@ -114,7 +119,7 @@ grammar LogStashConfig
   end
 
   rule hashentries
-    hashentry (whitespace hashentry)*
+    hashentry (cs hashentry)*
     <LogStash::Config::AST::HashEntries>
   end
 
diff --git a/logstash-core/spec/logstash/config/config_ast_spec.rb b/logstash-core/spec/logstash/config/config_ast_spec.rb
index b08152e6d9e..5851b11c8e3 100644
--- a/logstash-core/spec/logstash/config/config_ast_spec.rb
+++ b/logstash-core/spec/logstash/config/config_ast_spec.rb
@@ -211,6 +211,51 @@
         end
       end
     end
+
+    context "commentary in odd places" do
+      let(:config) { %q(
+        # early
+        input # bla
+        { # bla
+          plugin # bla
+          # bla
+          { # bla
+            # bla
+            arg  # bla
+            => # bla
+            bareword # bla
+            # bla
+            hasharg => {
+              #preentry
+              "firstkey" => "firstvalue"
+              # bla
+              "middle" # bla
+              # bla
+              => # bla
+              # bla
+              "midvalue"  # bla
+              # bla
+              "lastkey" => "lastvalue"
+              # bla
+            }
+          } # bla
+        # bla
+        } # bla
+        # comment ending in EOF:
+      ).strip }
+      subject { LogStashConfigParser.new }
+      def line_to_source(*args); end
+      def plugin(*args); end
+      it "hasn't got a trailing newline in the test config" do
+        # just to be clear that the last comment is supposed to end with EOF not \n
+        expect(config).not_to(end_with "\n")
+      end
+      it "should permit the comments" do
+        result = subject.parse(config)
+        expect(result).not_to(be_nil)
+        expect { eval(result.compile) }.not_to(raise_error)
+      end
+    end
   end
 
   context "when using two plugin sections of the same type" do