From: Ralf Baechle <ralf@linux-mips.org>
To: Daniel Jacobowitz <dan@debian.org>
Cc: linux-mips@linux-mips.org
Subject: Re: [PATCH] Fix TCP/UDP checksums on the Broadcom SB-1
Date: Tue, 20 Sep 2005 12:01:02 +0100 [thread overview]
Message-ID: <20050920110101.GA3159@linux-mips.org> (raw)
In-Reply-To: <20050920032818.GA7199@nevyn.them.org>
On Mon, Sep 19, 2005 at 11:28:18PM -0400, Daniel Jacobowitz wrote:
> The type of sum in csum_tcpudp_nofold is "unsigned int", so when we assign
> to it in an asm() block, and we're running on a system with 64-bit
> registers, it is vitally important that we sign extend it correctly before
> returning to C. Otherwise the stray high bits will be preserved into
> csum_fold, and on the SB-1 processor, 32-bit arithmetic on a non
> sign-extended register will yield surprising results.
>
> This caused incorrect checksums in some UDP packets for NFS root. The
> problem was mild when using a 10.0.1.x IP address, but severe when
> using 192.168.1.x.
Good catch. And just to increase the func factor this bug did also apply
to 2.4. Applied,
Ralf
prev parent reply other threads:[~2005-09-20 11:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-20 3:28 [PATCH] Fix TCP/UDP checksums on the Broadcom SB-1 Daniel Jacobowitz
2005-09-20 10:43 ` Maciej W. Rozycki
2005-09-20 11:00 ` Matej Kupljen
2005-09-20 11:06 ` Ralf Baechle
2005-09-20 14:26 ` Michael Uhler
2005-09-20 14:26 ` Michael Uhler
2005-09-20 14:59 ` Ralf Baechle
2005-09-20 11:01 ` Ralf Baechle [this message]
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