Re: [PATCH 50/51] net/core/flow.c: Fix CPU hotplug callback registration

From: David Miller <davem@davemloft.net>
Date: Thu, 06 Feb 2014 20:39:21 -0800 (PST)

From: "Srivatsa S. Bhat" <redacted>
Date: Thu, 06 Feb 2014 03:43:46 +0530

quoted

Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

 ...

quoted

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

 ...

quoted

Fix the code in net/core/flow.c by using this latter form of callback
registration.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Li RongQing <redacted>
Cc: Sasha Levin <redacted>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <redacted>
Cc: netdev@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat <redacted>

Applied.

I just realized that this has a dependency not in the 'net'
tree, so I reverted and assume you will merge this with the
patch that provides the necessary interface(s).

Signed-off-by: David S. Miller <davem@davemloft.net>