On Tue, Nov 16, 2010 at 5:31 PM, Kyle McMartin <kyle@mcmartin.ca> wrote:
>
> This is a bit of a problem, as it's called in_atomic context and kmalloc's
> under GFP_KERNEL (which can sleep.) This results in sleep-under-spinlock
> prints when CONFIG_DEBUG_SPINLOCK_SLEEP=y.

Blame me, I threw that out as a single point where this can be done.

In fact, holding the signal spinlock was seen as a bonus, since that
was used to serialize the access to the signal->autogroup access.
Which I think is required.

But yes, it does create problems for the allocation. It could be done
as just a GFP_ATOMIC, of course, and on allocation failure you'd just
punt and not do it. Not pretty, but functional.

                  Linus