net: net_enable_timestamp() can be called from irq contexts
authorEric Dumazet <edumazet@google.com>
Wed, 1 Mar 2017 22:28:39 +0000 (14:28 -0800)
committerDavid S. Miller <davem@davemloft.net>
Thu, 2 Mar 2017 04:55:57 +0000 (20:55 -0800)
commit13baa00ad01bb3a9f893e3a08cbc2d072fc0c15d
treeebcc0624dcccf6c25949f3e52c26a75f542bb7b8
parent540e2894f7905538740aaf122bd8e0548e1c34a4
net: net_enable_timestamp() can be called from irq contexts

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@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/dev.c