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List:       linux-kernel
Subject:    Re: 2.2.17 --- extreme format string weirdness in /proc
From:       Jesse Pollard <pollard () cats-chateau ! net>
Date:       2000-09-30 21:00:07
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On Sat, 30 Sep 2000, Nix wrote:
>Andries Brouwer <aeb@veritas.com> writes:
>
>> On Sat, Sep 30, 2000 at 03:09:10PM +0100, Nix wrote:
>> 
>> > Yesterday, I noticed that netstat had stopped working on my 2.2.17 box
>> > The reason is fairly self-evident:
>> > 
>> > : loki:/# cat /proc/net/dev
>> ...
>> > :     lo:%lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu
>> > :   eth0:%lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu
>> 
>> This could be explained by a single-bit corruption of your kernel,
>> namely if the place where printk tests a format character against '%'
>> is broken. Maybe the '%' is bad, or maybe the comparison instruction.
>
>Agreed. /proc/{pid}/stat backs you up there too. %u is fine, only %lu is
>mangled by something.
>
>It's certainly an amusing failure; I'm surprised by how well everything
>runs with the system in this state; netstat and top fall over, uptime
>calculations go wrong, and ps and inndwatch complain. Everything else is
>happy as could be.
>
>
>Whatever it is it probably isn't memory error; I do lots of gcc
>compilations on this machine, and don't get nonrepeatable bootstrap
>comparison failures...
>
>I'll try pulling out some of the patches and modules (lm-sensors can go
>easily; reiserfs not so easily) and see what happens.

Check back a few weeks in the archives - I think this has to do with some
compiler issues where %lu isn't done because printk couldn't do the conversion.
I seem to remember that a patch was provided too...
                               
-- 
-------------------------------------------------------------------------
Jesse I Pollard, II
Email: pollard@cats-chateau.net

Any opinions expressed are solely my own.
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