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Subject: Re: Multithreaded coredump patch where?
From: Arjan van de Ven <arjanv@redhat.com>
To: Roberto Fichera <kernel@tekno-soft.it>
Cc: linux-kernel@vger.kernel.org
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On Tue, 2002-12-17 at 12:05, Roberto Fichera wrote:
> At 13.21 16/12/02 -0800, mgross wrote:
>=20
> >I haven't rebased the patches I posted back in June for a while now.
> >
> >Attached is the patch I posted for the 2.4.18 vanilla kernel.  Its a bit
> >controversial, but it seems to work for a number of folks.  Let me know =
if
> >you have any troubles re-basing it.
>=20
> Only one hunk failed on include/asm-ia64/elf.h but fixed by hand.
> Why do you say a bit controversial ?

The design has theoretical (but probably in practice not trivial to
trigger) deadlocks; by design it prevents processes that are sleeping
from running, regardless whether those processes are in kernel space or
not. If they are in kernel space, they can accidentally be holding a
semaphore that something in the core dumping path will need to get (but
can't because it never will be released). There are not that many of
such semaphores (kmap semaphore is one, and filesystems can have several
internally)


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