Re: [BUG linux-2.6.15-rc] process events connector - soft lockupdetected

[Paul Jackson]

Andrew wrote:
> I note that copy_process() also calls cpuset_fork() under
> write_lock_irq(&tasklist_lock) which is a) inefficient and b) forbidden
> according to the nice comment over task_lock().

Nice catch - thanks.  It was (perhaps) only inefficient until recently, because
cpuset_fork() didn't do any locking - just an atomic cpuset counter increment.

But with the locking overhaul that went into Linus's tree Oct 31, 2005,
cpuset_fork() now takes task_lock(), to guard against cpuset.c attach_task()
invalidating the task->cpuset pointer as cpuset_fork is dereferencing it.

I will look into preparing a patch that moves cpuset_fork() outside the
write_lock_irq().

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@xxxxxxx> 1.925.600.0401
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/