Bug 10005 - Mono crash instead throwing OutOfMemory exception
Summary: Mono crash instead throwing OutOfMemory exception
Status: RESOLVED INVALID
Alias: None
Product: Runtime
Classification: Mono
Component: GC ()
Version: unspecified
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2013-02-03 15:34 UTC by Sergey Zhukov
Modified: 2013-02-13 17:05 UTC (History)
4 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED INVALID

Description Sergey Zhukov 2013-02-03 15:34:05 UTC
Mono crashes in such test case:

using System;
using System.Collections.Generic;

namespace mt3
{
	class MainClass
	{
		public static void Main(string[] args)
		{
			List<byte[]> test = new List<byte[]>();
			
			for (int i=0; i<int.MaxValue; i++)
			{
				test.Add(new byte[10000]);
			}
		}
	}
}

mono-sgen ./mt3.exe
* Assertion at sgen-gc.c:2221, condition `mem' not met

Stacktrace:

  at (wrapper managed-to-native) object.__icall_wrapper_mono_gc_alloc_vector (intptr,intptr,intptr) <0xffffffff>
  at (wrapper alloc) object.AllocVector (intptr,intptr) <0xffffffff>
  at mt3.MainClass.Main (string[]) <0x0004b>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object (object,intptr,intptr,intptr) <0xffffffff>

instead of crashing mono should raise OutOfMemory exception

Environment:
Mono JIT compiler version 2.10.8.1 (Debian 2.10.8.1-1~dhx1~lucid1)
Ubuntu 10.04 (32 bit)
4Gb of RAM
Comment 1 Sergey Zhukov 2013-02-05 05:20:43 UTC
I ran this test case in mono 3.0.4. The result is correct.

 mono-sgen ./mt3.exe

Unhandled Exception:
OutOfMemoryException
[ERROR] FATAL UNHANDLED EXCEPTION: System.OutOfMemoryException: Out of memory
  at (wrapper managed-to-native) object:__icall_wrapper_mono_gc_alloc_vector (intptr,intptr,intptr)
  at (wrapper alloc) object:AllocVector (intptr,intptr)
  at mt3.MainClass.Main (System.String[] args) [0x00000] in <filename unknown>:0 

Environment:
Mono JIT compiler version 3.0.4 (master/0e6393e Mon Feb  4 14:03:01 PST 2013)
Ubuntu 12.04 (32 bit)
768M of RAM

Also, I noticed difference in memory allocation. mono-sgen 2.10.8 allocates only free memory, without using swap and crashes in case of out of memory. mono-sgen 3.0.4 allocates free memory and whole free swap and only then throw OutOfMemoryException or was killed by oom killer.
Comment 2 Rodrigo Kumpera 2013-02-12 12:40:14 UTC
mono does alloc as much memory as you let it to. This is the normal behavior of any program you run.

I suggest you limit the amount of managed memory mono can allocate and in the meanwhile try to find the memory leaks in your app.
Comment 3 Sergey Zhukov 2013-02-13 14:58:19 UTC
I don't understand your point. Do you mean, that hard crash of mono instead of throwing OutOfMemoryException is normal behaviour? In this bug I didn't tell about memory leaks, what I've just said, that mono 2.10 must throw OutOfMemoryException when there is no enough memory but not to crash.
Comment 4 Rodrigo Kumpera 2013-02-13 17:05:48 UTC
Use mono 3.0.0. 2.10 is not longer publicly maintained.