Coredump when program run as root?

Coredump when program run as root?

[Ralf Hildebrandt]

I found this while trying to find out why squid doesn't produce a core
file:

http://lists.samba.org/archive/samba-technical/2002-August/023576.html

Most UNIX variants disable core dumps in programs that have changed their
uid or euid during operation.  This includes Solaris and Linux.

Well, squid does exactly that. How can I still get a coredump? I really
need one. Kernel 2.6.11.7

-- 
Ralf Hildebrandt (i.A. des IT-Zentrum)          Ralf.Hildebrandt@charite.de
Charite - Universitätsmedizin Berlin            Tel.  +49 (0)30-450 570-155
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Re: Coredump when program run as root?

[Michael Tokarev]

Ralf Hildebrandt wrote:
> I found this while trying to find out why squid doesn't produce a core
> file:
> 
> http://lists.samba.org/archive/samba-technical/2002-August/023576.html
> 
> Most UNIX variants disable core dumps in programs that have changed their
> uid or euid during operation.  This includes Solaris and Linux.
> 
> Well, squid does exactly that. How can I still get a coredump? I really
> need one. Kernel 2.6.11.7

Not in stock kernel, no.
There's a patch in -ac series which implements 'suid_dumpable' attribute.
It is included with RedHat kernels I think.
The fun stuff is that I wasn't able to use the functionality anyway (i
had similar but a bit worse problem) -- regardless of how hard i tried,
it didn't produce any core dumps ;)

/mjt

P.S.  Hi, Ralf! The world is too small! ;)

Re: Coredump when program run as root?

[Bodo Eggert <harvested.in.lkml@posting.7eggert.dyndns.org>]

Ralf Hildebrandt <Ralf.Hildebrandt@charite.de> wrote:

> Most UNIX variants disable core dumps in programs that have changed their
> uid or euid during operation.  This includes Solaris and Linux.
> 
> Well, squid does exactly that. How can I still get a coredump? I really
> need one. Kernel 2.6.11.7

It cannot change the (e)uid if it is run as user. Maybe this helps.
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