[prev in list] [next in list] [prev in thread] [next in thread] 

List:       linux-wireless
Subject:    Re: [PATCH v8] ath9k: let sleep be interrupted when unregistering hwrng
From:       "Jason A. Donenfeld" <Jason () zx2c4 ! com>
Date:       2022-06-30 14:03:31
Message-ID: Yr2tM4fX4YjOSQxh () zx2c4 ! com
[Download RAW message or body]

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
[prev in list] [next in list] [prev in thread] [next in thread]