Re: [Patch v4 1/2] freezer: check OOM kill while being frozen

[Rafael J. Wysocki]

On Wednesday, September 10, 2014 12:23:36 AM Tejun Heo wrote:
> On Tue, Sep 09, 2014 at 05:16:55PM +0200, Michal Hocko wrote:
> > But OOM killer doesn't kill kernel threads as they do not own any
> > memory. So the check should be safe, no?
> 
> Even for userland tasks, try_to_freeze() can currently be anywhere in
> the kernel.  The frequently used ones are few but there are some odd
> ones out, and, again, there's nothing enforcing any structure on
> try_to_freeze() usage.  The other thing is that we may do quite a bit
> during exiting including allocating memory.  Are those safe for system
> PM?  Rafael, what exactly are the rules for PM?  What shouldn't
> change?

We can't make any assumptions regarding the availability of any devices.
That is, whatever can end up in device access may potentially fail.

Rafael

--
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/