Re: [PATCH v8] ath9k: let sleep be interrupted when unregistering hwrng

Gregory Erwin
2022-07-01T01:17:37Z

On Thu, Jun 30, 2022 at 7:03 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> Hey Gregory,
>
> On Wed, Jun 29, 2022 at 01:42:40PM +0200, Jason A. Donenfeld wrote:
> > There are two deadlock scenarios that need addressing, which cause
> > problems when the computer goes to sleep, the interface is set down, and
> > hwrng_unregister() is called. When the deadlock is hit, sleep is delayed
> > for tens of seconds, causing it to fail. These scenarios are:
> >
> > 1) The hwrng kthread can't be stopped while it's sleeping, because it
> > uses msleep_interruptible() instead of schedule_timeout_interruptible().
> > The fix is a simple moving to the correct function. At the same time,
> > we should cleanup a common and useless dmesg splat in the same area.
> >
> > 2) A normal user thread can't be interrupted by hwrng_unregister() while
> > it's sleeping, because hwrng_unregister() is called from elsewhere.
> > The solution here is to keep track of which thread is currently
> > reading, and asleep, and signal that thread when it's time to
> > unregister. There's a bit of book keeping required to prevent
> > lifetime issues on current.
> >
> > Reported-by: Gregory Erwin <gregerwin256@gmail.com>
> > Cc: Toke Høiland-Jørgensen <toke@redhat.com>
> > Cc: Kalle Valo <kvalo@kernel.org>
> > Cc: Rui Salvaterra <rsalvaterra@gmail.com>
> > Cc: Herbert Xu <herbert@gondor.apana.org.au>
> > Cc: stable@vger.kernel.org
> > Fixes: fcd09c90c3c5 ("ath9k: use hw_random API instead of directly dumping into random.c")
> > Link: https://lore.kernel.org/all/CAO+Okf6ZJC5-nTE_EJUGQtd8JiCkiEHytGgDsFGTEjs0c00giw@mail.gmail.com/
> > Link: https://lore.kernel.org/lkml/CAO+Okf5k+C+SE6pMVfPf-d8MfVPVq4PO7EY8Hys_DVXtent3HA@mail.gmail.com/
> > Link: https://bugs.archlinux.org/task/75138
> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
>
> Hoping for your `Tested-by:` if this still works for you.
>
> Jason

Apologies for the delay.
Tested-by: Gregory Erwin <gregerwin256@gmail.com>