Re: [Gnu-arch-users] [BUG] New bug report for 1k barrier PANIC

[James Blackwell]

Robert Anderson wrote:
> // arch-tag: df5fee29-4522-4f55-a800-1a6a8d304deb 
>
> Therefore it seems that there is NO TRUNCATION of the tag.  This
> seems to be the main point of confusion.
>
> Now, using GNU tla 1.2.1:
>
> % ~/linux-packages/tla-1.2.1/bin/tla changes
>
> [snip output]
> PANIC: Top-of-file arch tag crosses 1k boundary

Among the many bugs _already existing_ bugs that this seems to be
exercising, one of them looks like there's an off by one on the
begin tag code. It tla detects and end-of-file tag, it reads all but 
the very last byte (credit to jivera for finding this).

Delete 1 byte from earlier in the file and add one extra newline to the
end, and see if the warning goes away. If it does, put the file back to
the way it was and on or about, 1385 of libarch/invids.c change the
following:

  if (0 > vu_lseek (errn, file_fd, -1026, SEEK_END))
         to 
  if (0 > vu_lseek (errn, file_fd, - sizeof(buf), SEEK_END))

That will help jivera and I verify that jivera's hunch is right.


> So, there is a problem here which is independent of any id-tag
> truncation issue.  I don't see how this can't be considered a bug
> of high severity.

Bob, who gave you the impression that they didn't think this is
important? I mean, sure, I'm not running around with my hair on fire,
but I promise you that I do think its very, very very important.

Maybe you have the wrong impression because the fix is going through the
normal process. We're going to do that because the *last* thing we
should do is panic and start throwing random changes into the tree to
fix the problem 5 broken ways. Instead, lets do it right, and fix it
*once*.

If you can't wait the two weeks (and you strike me as someone that
can't), then I suggest you do one of the following: 

  * downgrade to 1.2.0
  * use my 1.2.1
  * build tla using my tla-dev. That has downgraded the panic to a
    warning.


I mentioned two in the previous email. Why haven't you done either of
these yet? Are you using debian or something, and you're waiting for
somebody to build the software for you? 

> It is interesting to note:
>
> % wc --bytes file
>    1025 file
>
> I hope this is useful in fixing the bug.

That may become very interesting if your tag is at the very end of the
file.

-- 
James Blackwell          Try something fun: For the next 24 hours, give
Smile more!              each person you meet a compliment!

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