Coda File System

Re: Repeated Segfault in Server

From: Martin Ginkel <>
Date: Wed, 12 Apr 2006 04:23:00 -0400
Martin Ginkel wrote:
> I have repeated errors in one of my servers on a non-replicated volume.
> I have stored some files on my client, and IMHO not synchronized yet.
> Whenever I am authenticated on that client and the client and server
> are online, the server goes down with segfault.
> I cant recover from this situation. The location appearing in GDB is
> sftp3.c:362
> if (pb->Header.TimeEcho >= pBuff->Header.TimeEcho &&
>             !(pb->Header.SEFlags & SFTP_COUNTED)) {
>             dataThisRound += pb->Prefix.LengthOfPacket;
>             pb->Header.SEFlags |= SFTP_COUNTED;
>             }

OK, after some debugging session I found the source of the problem myself:

I configured 'windowsize' in the server.conf to 128
This is bad, because it apparently must be lower than
MAXOPACKETS defined in sftp.h.
(This constraint is somewhere in the documentation of that header)
I tried to increase that define to 256, but then I had yet another
assertion failing, which requiered that MAXOPACKETS / 32 should be
<= 2.

So MAXOPACKETS must be 64 and windowsize must be <= 64, although I
had apparently a bit more performance with larger windows.


+-[Martin Ginkel]-------------[mailto:mginkel(at)]-+
| MPI Magdeburg, Zi S2.09    Sandtorstr. 1, D-39106 Magdeburg, Germany |
| Computers are not intelligent, they only think they are.             |
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Received on 2006-04-12 08:27:47