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(-) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
