Re: shm updates broke UML

From: Vasiliy Kulikov
Date: Mon Aug 01 2011 - 13:25:05 EST


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
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