"Jason A. Donenfeld" <Jason@xxxxxxxxx> writes:
> 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@xxxxxxxxx>
> Cc: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
> Cc: Kalle Valo <kvalo@xxxxxxxxxx>
> Cc: Rui Salvaterra <rsalvaterra@xxxxxxxxx>
> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: fcd09c90c3c5 ("ath9k: use hw_random API instead of directly dumping into random.c")
> Link: https://lore.kernel.org/all/CAO+Okf6ZJC5-nTE_EJUGQtd8JiCkiEHytGgDsFGTEjs0c00giw@xxxxxxxxxxxxxx/
> Link: https://lore.kernel.org/lkml/CAO+Okf5k+C+SE6pMVfPf-d8MfVPVq4PO7EY8Hys_DVXtent3HA@xxxxxxxxxxxxxx/
> Link: https://bugs.archlinux.org/task/75138
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
> ---
> Changes v7->v8:
> - Add a missing export_symbol.
>
> drivers/char/hw_random/core.c | 30 ++++++++++++++++++++++++----
> drivers/net/wireless/ath/ath9k/rng.c | 19 +++++++-----------
> kernel/sched/core.c | 1 +
> 3 files changed, 34 insertions(+), 16 deletions(-)
I don't see any acks for the hw_random and the scheduler change, adding more
people to CC. Full patch here:
https://patchwork.kernel.org/project/linux-wireless/patch/20220629114240.946411-1-Jason@xxxxxxxxx/
Are everyone ok if I take this patch via wireless-next?
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