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Message-Id: <20170301.205816.1158665690798472665.davem@davemloft.net>
Date: Wed, 01 Mar 2017 20:58:16 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: eric.dumazet@...il.com
Cc: edumazet@...gle.com, dvyukov@...gle.com, netdev@...r.kernel.org
Subject: Re: [PATCH net] net: net_enable_timestamp() can be called from irq
contexts
From: Eric Dumazet <eric.dumazet@...il.com>
Date: Wed, 01 Mar 2017 14:28:39 -0800
> From: Eric Dumazet <edumazet@...gle.com>
>
> It is now very clear that silly TCP listeners might play with
> enabling/disabling timestamping while new children are added
> to their accept queue.
>
> Meaning net_enable_timestamp() can be called from BH context
> while current state of the static key is not enabled.
>
> Lets play safe and allow all contexts.
>
> The work queue is scheduled only under the problematic cases,
> which are the static key enable/disable transition, to not slow down
> critical paths.
>
> This extends and improves what we did in commit 5fa8bbda38c6 ("net: use
> a work queue to defer net_disable_timestamp() work")
>
> Fixes: b90e5794c5bd ("net: dont call jump_label_dec from irq context")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
Applied and queued up for -stable.
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