Re: Linux 2.6.27.27

From: Marc Dionne
Date: Mon Jul 20 2009 - 22:39:05 EST


On 07/20/2009 09:05 PM, Linus Torvalds wrote:

On Mon, 20 Jul 2009, Marc Dionne wrote:
It could be ccache too, of course.
Actually in my case it turns out that it is ccache after all - if I remove it
from the picture everything is fine. If I re-enable it, even with a clean
cache, I get the problem.

It might just be a coincidence that it's triggered by the -fwrapv change.

Btw, do you find any core-files lying around if you enable them before the
build with

ulimit -c unlimited

or similar?

And how did you clean ccache? There's "-c" and then there's "-C".

Linus

Unfortunately I'm not able to reproduce anymore, after clearing /var/cache/ccache completely (rm -rf). Earlier I had done ccache -C, which didn't help. I didn't think to copy the contents for more analysis.

So perhaps a combination of some odd ccache state along with changing gcc, binutils (which I updated today) and the compile flag. Revving binutils and gcc back and forth didn't reproduce it.

What is odd though is that when I straced a single gcc command line that produced an empty .o file, it looked normal - a series of successful writes with the correct amount of data to a temp file, close, unlink .o file, rename temp file -> .o file. But the resulting file was empty. Make me wonder if there was something filesystem/caching related to it.

Marc
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