lkml.org 
[lkml]   [2022]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v6] ath9k: sleep for less time when unregistering hwrng
On Tue, Jun 28, 2022 at 12:46 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> Hi Gregory,
>
> On Tue, Jun 28, 2022 at 3:39 AM Gregory Erwin <gregerwin256@gmail.com> wrote:
> >
> > On Mon, Jun 27, 2022 at 5:18 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
> > >
> > > "Jason A. Donenfeld" <Jason@zx2c4.com> writes:
> > >
> > > > Even though hwrng provides a `wait` parameter, it doesn't work very well
> > > > when waiting for a long time. There are numerous deadlocks that emerge
> > > > related to shutdown. Work around this API limitation by waiting for a
> > > > shorter amount of time and erroring more frequently. This commit also
> > > > prevents hwrng from splatting messages to dmesg when there's a timeout
> > > > and switches to using schedule_timeout_interruptible(), so that the
> > > > kthread can be stopped.
> > > >
> > > > Reported-by: Gregory Erwin <gregerwin256@gmail.com>
> > > > Tested-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>
> > >
> > > Gregory, care to take this version for a spin as well to double-check
> > > that it still resolves the issue? :)
> > >
> > > -Toke
> > >
> >
> > With patch v6, reads from /dev/hwrng block for 5-6s, during which 'ip link set
> > wlan0 down' will also block. Otherwise, 'ip link set wlan0 down' returns
> > immediately. Similarly, wiphy_suspend() consistently returns in under 10ms.
> >
> > Tested-by: Gregory Erwin <gregerwin256@gmail.com>
>
> Oh 5-6s... so it's actually worse. Yikes. Sounds like v4 might have
> been the better patch, then?

$ curl https://lore.kernel.org/lkml/20220627104955.534013-1-Jason@zx2c4.com/raw
| git am

That one, if you want to give it a spin and see if that 5-6s is back
to ~1s or less.

Jason

\
 
 \ /
  Last update: 2022-06-28 12:49    [W:0.078 / U:0.332 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site