Re: Spinlock bug??

JWM
2007-01-25T21:49:10Z

Simon;
I've looked at the code and the function that calls
cpuset_set_cpus_affinity does a get_task. That bumps the usage count and
should protect from an exiting process doing evil - shouldn't it?
So the sched_setaffinity locks, bumps the task useage and then unlocks
and calls cpuset_set_cpus_affinity. The in the Bull code
cpuset_set_cpuaffinity takes a spin lock on the structure and then
(potentially) moves it to another CPU.
It doesn't look like a change is required other than removing the lock
in cpuset_set_cpus_affinity.
Is there a possible race here I'm missing?
....JW
----- Original Message -----
From: "Simon Derr" <Simon.Derr@bull.net>
To: "JWM" <jwm@systemfabricworks.com>
Cc: <linux-ia64@vger.kernel.org>; "Philippe Garrigues"
<philippe.garrigues@bull.net>
Sent: Thursday, January 25, 2007 3:12 AM
Subject: Re: Spinlock bug??

>> Hi all;
>> I'm working on a Bull - 8 way ia64 system running a RedHat variant of
>> 2.6.17.
>> I keep getting a spin lock bug and dump , attached.
>
> Hello,
>
> If you are running a Bull Linux kernel, I suggest that you contact
> directly Bull for this kind of issues. We have added a few custom patches
> that could hardly be adressed by other people from this list.
>
> That being said, I'm going to see what's going on in this particular case.
> You're probably right.
>
> Simon.
>
>
>
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