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Date: Mon, 1 Aug 2011 21:24:52 +0400
From: Vasiliy Kulikov <segoon@openwall.com>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Richard Weinberger <richard@nod.at>, serge.hallyn@canonical.com,
        torvalds@linux-foundation.org, akpm@linux-foundation.org,
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Subject: Re: shm updates broke UML
Message-ID: <20110801172452.GA26190@albatros>
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On Mon, Aug 01, 2011 at 19:19 +0200, Marc Zyngier wrote:
> Here you go (sorry about the line wrapping, damned webmail...):

Thank you!  Now I see that the problem is rw_mutex is not initialized:

	down_write(&shm_ids(ns).rw_mutex);

void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
{
    ...
	if (sem->activity == 0 && list_empty(&sem->wait_list)) {
                                         ^^^^^^^^^^^^^^^ is NULL

Wtf - ipc namespace should be fully initialized for the moment of
threads run...

> Calibrating local timer... 104.99MHz.
> CPU1: Booted secondary processor
> CPU1: Unknown IPI message 0x1
> CPU2: Booted secondary processor
> CPU2: Unknown IPI message 0x1
> CPU3: Booted secondary processor
> CPU3: Unknown IPI message 0x1
> Brought up 4 CPUs
> SMP: Total of 4 processors activated (333.41 BogoMIPS).
> ns = c0447474, ids = c04474d0
> ns = c0447474, ids = c04474d0
> wait_list = c04474e0
> next =   (null)
           ^^^^^^

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments