Re: 2.6.25.3: su gets stuck for root

Vegard Nossum
2008-06-02T14:31:21Z

On Mon, Jun 2, 2008 at 2:28 PM, Alan Cox <alan@redhat.com> wrote:
> On Mon, Jun 02, 2008 at 12:57:07PM +0200, Vegard Nossum wrote:
>> I guess this still doesn't explain why TTOU doesn't block (IOW, stop
>> the process, right?) in this case, because my test program does not
>> touch it.
>
> I see the parent process sleeping and the child taking TTOU and going to
> state T. That again is correct.
>
> alan 3219 0.0 0.0 3652 384 pts/5 S 13:11 0:00 ./repro
> alan 3220 0.0 0.0 3652 204 pts/5 T 13:11 0:00 ./repro
>
> If you run it without any straces etc do you see it blocked in T or sitting
> in R ?

Without any straces, it is blocked in T. Like Joe's report.

With strace, it's in R.

Exactly as you said, correct and expected behaviour.

So this is not a kernel problem at all.

I'm sorry for having wasted your time :-(

Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036