Re: Fw: 2.5.61 oops running SDET

From: Linus Torvalds (torvalds@transmeta.com)
Date: Sun Feb 16 2003 - 18:32:22 EST


On Sun, 16 Feb 2003, Martin J. Bligh wrote:
>
> So what does protect sighand? tasklist_lock?

Yup. At least right now. And we do tend to hold tasklist_lock in most
cases simply by virtue of having to get it anyway in order to search for
the process.

> It doesn't seem to
> as people do things like:
>
> spin_unlock_irq(&current->sighand->siglock);
>
> all the time ... so is it just protected by good faith and the direction
> of the wind?

Agreed. That, and the fact that most of the time the stuff _is_ there:
obviously any time the process looks at its own signals it will always be
there.

So we have two cases:
 - "normal" signal sending which holds tasklist_lock to find the target.
 - signals to the process itself, which is usually safe, since we know
   we're there (the exception would be if/when taking a fault in the exit
   path, but even that might be ok since signals are torn down not by exit
   itself but by "release_task")

So the signal path may actually be ok.

                Linus

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