Bug 16796 - getting Houston... exception with xsp when using mod_mono module for apache 2.4 during file upload
Summary: getting Houston... exception with xsp when using mod_mono module for apache 2...
Status: NEW
Alias: None
Product: Class Libraries
Classification: Mono
Component: General ()
Version: 2.10.x
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2013-12-13 23:10 UTC by Carl
Modified: 2014-10-10 14:22 UTC (History)
1 user (show)

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

patch for mod_mono 2.10 for apache 2.4 (3.61 KB, patch)
2013-12-13 23:10 UTC, Carl

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Description Carl 2013-12-13 23:10:29 UTC
Created attachment 5659 [details]
patch for mod_mono 2.10 for apache 2.4


architecture: x64
Bunutils: 2.20.1a
GCC: 4.6.4
eglibc: 2.13
GDB Server: 7.4.1
Arch: x86_64
Linux Kernel 3.2.51


apr 1.5.0
apr-util 1.5.3
httpd 2.4.7
mono 2.10.8
libgdiplus 2.10
xsp 2.10.2
mod_mono 2.10


I applied a patch against mod_mono so that I can compile it with apache 2.4, will include that.

I have an asp.net website that allows you to upload a file.  The file is around 120 MB in size.  I am using the jquery qq-upload control to upload the file.  It shows the percentage as it is being uploaded.

I was getting an exception "Houston..." most of the time when the upload was very quick, since it was from a computer in the same network.  It also happens when the upload is slow sometimes, but never if the computer was a virtual machine.  Only if it was running on the hardware directly.

I found it was coming from this file:


It came from this section of it:

public int GetClientBlock ([Out] byte [] bytes, int position, int size) 
	if (SetupClientBlock () != 0) return 0;

	 * turns out that that GET_CLIENT_BLOCK (ap_get_client_block) can
	 * return -1 if a socket is closed
	writer.Write ((int) ModMonoCmd.GET_CLIENT_BLOCK);
	writer.Write (size);
	Send ();
	FillBuffer (4);
	int i = reader.ReadInt32 ();
	if (i == -1)
		return -1;
	if (i > size)
		throw new Exception ("Houston...");

	FillBuffer ((uint)i);
	return reader.Read (bytes, position, i);

When I included what values i and size are checking with, I got these results from 4 attempts:

GetClientBlock Exception (i>size): i = 960779623 size = 32768
GetClientBlock Exception (i>size): i = 1633895019 size = 32768
GetClientBlock Exception (i>size): i = 927229250 size = 32768
GetClientBlock Exception (i>size): i = 1817601579 size = 32768

So the variable i, never seems to be the same value when this happens.
Comment 1 Carl 2014-10-10 14:22:52 UTC
I have found that running xsp2 or xsp4 does not cause this exception to show up.  So the problem is definitely with the apache module mod_mono.

I want to use FastCGI to run mono, but there is no sample configurations out there.