Re: lots of 2.2.4 oopses

Nicholas Henke (henken@seas.upenn.edu)
Wed, 24 Mar 1999 15:18:14 -0500


I noticed similarily flaky performance with egcs....my box would do some
randowm weird things. I recomilied with gcc 2.7.2.3 on the same wetup...all
seems fine now.
Nic

On Wed, 24 Mar 1999, Linus
Torvalds wrote: > In article <36F92EBB.B33E673E@pobox.com>,
> Valient Gough <vgough@pobox.com> wrote:
> >
> >I upgraded from 2.2.3 to 2.2.4 last night. Since then I've had to
> >lockups. The second one managed to log "Unable to handle kernel paging
> >request at virtual address 00de3f9c" before it locked up, but I didn't
> >have the correct System.map file in place, so klogd didn't have symbols.
> >
> >But, this morning, I had 4 such oops in a row, with a correct
> >System.map.
>
> Ok, they are all basically the same oops, the file pointer list has
> gotten corrupted somehow, and that corruption will result in an oops
> whenever the kernel tries to touch one of the file pointers.
>
> The oops happens in remove_filp() (which is an inline function,
> explaining why the symbol table says it is in get_empty_filp()).
>
> The code looks like
>
> if(file->f_next)
> file->f_next->f_pprev = file->f_pprev;
> *file->f_pprev = file->f_next;
>
> and the thing oopses apparently because file->f_next is just crap (it
> appears to have the value 0x2c302c35, to be exact - seems to be the
> string "5,0," in fact).
>
> I would _much_ prefer it if you could try to compile 2.2.4 with
> gcc-2.7.2. We now have two reports of an oops like this, and in both
> cases egcs was used as the compiler. And egcs is doing alias analysis
> these days - and following the ANSI rules about aliases is something
> that we haven't validated that the kernel is doing correctly (and that's
> assuming that egcs is bug-free, which is obviously also a potential
> issue).
>
> Basically, right now I don't know whether this is (a) a real kernel bug
> (b) the kernel having some place it is not alias analysis aware and
> doing something ugly that breaks with egcs or (c) an egcs bug.
>
> Compiling with gcc-2.7.2 would at least resolve whether it is the
> compiler that induces the effect..
>
> Linus
>
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--
Nicholas Henke
University of Pennsylvania 
Class of 2002
215-417-6418
Linux User # 97849
----------------------
"To be sure of hitting the target, shoot first, and call whatever you hit the target"
----------------------
"I'm confused, but it's working, and I'm sure I'll understand it eventually."

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