On Fri, 28 Jun 2019 07:12:07 -0700, John Fastabend wrote:
> Yeah seems possible although never seen in my testing. So I'll
> move the test_bit() inside the lock and do a ctx check to ensure
> still have the reference.
>
> CPU 0 (free) CPU 1 (wq)
>
> lock(sk)
> lock(sk)
> set_bit()
> cancel_work()
> release
> ctx = tls_get_ctx(sk)
> unlikely(!ctx) <- we may have free'd
> test_bit()
> ...
> release()
>
> or
>
> CPU 0 (free) CPU 1 (wq)
>
> lock(sk)
> lock(sk)
> ctx = tls_get_ctx(sk)
> unlikely(!ctx)
> test_bit()
> ...
> release()
> set_bit()
> cancel_work()
> release
Hmm... perhaps it's cleanest to stop the work from scheduling before we
proceed?
close():
while (!test_and_set(SHED))
flush();
lock(sk);
...
We just need to move init work, no?
FWIW I never tested his async crypto stuff, I wonder if there is a way
to convince normal CPU crypto to pretend to be async?
