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SubjectRe: [PATCH 0/3] static keys: fix test/set races

Cleaning out my INBOX I found this patch series. It seems to have been
forgotten about. It ended up with Ingo and Peter agreeing with the way
things should be done and I thought Jason was going to send an update.
But that seems to never have happened.

Does this patch series still look legit? Should we pursue it?

-- Steve

On Fri, 28 Jun 2013 22:30:28 +0000 (GMT)
jbaron@akamai.com wrote:

> Hi,
>
> As pointed out by Andi Kleen, some static key users can be racy because they
> check the value of the key->enabled, and then subsequently update the branch
> direction. A number of call sites have 'higher' level locking that avoids this
> race, but the usage in the scheduler features does not. See:
> http://lkml.indiana.edu/hypermail/linux/kernel/1304.2/01655.html
>
> Thus, introduce a new API that does the check and set under the
> 'jump_label_mutex'. This should also allow to simplify call sites a bit.
>
> Users of static keys should use either the inc/dec or the set_true/set_false
> API.
>
> Thanks,
>
> -Jason
>
>
> Jason Baron (3):
> static_keys: Add a static_key_slow_set_true()/false() interface
> sched: fix static keys race in sched_feat
> udp: make use of static_key_slow_set_true() interface
>
> Documentation/static-keys.txt | 8 ++++++++
> include/linux/jump_label.h | 30 ++++++++++++++++++++++++++++++
> kernel/jump_label.c | 40 ++++++++++++++++++++++++++++++++++++++++
> kernel/sched/core.c | 12 +++++-------
> kernel/sched/sched.h | 10 +++++-----
> net/ipv4/udp.c | 9 ++++-----
> net/ipv6/udp.c | 9 ++++-----
> 7 files changed, 96 insertions(+), 22 deletions(-)
>



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