linux/kernel/sched
Ben Segall 51f2176d74 sched/fair: Fix unlocked reads of some cfs_b->quota/period
sched_cfs_period_timer() reads cfs_b->period without locks before calling
do_sched_cfs_period_timer(), and similarly unthrottle_offline_cfs_rqs()
would read cfs_b->period without the right lock. Thus a simultaneous
change of bandwidth could cause corruption on any platform where ktime_t
or u64 writes/reads are not atomic.

Extend cfs_b->lock from do_sched_cfs_period_timer() to include the read of
cfs_b->period to solve that issue; unthrottle_offline_cfs_rqs() can just
use 1 rather than the exact quota, much like distribute_cfs_runtime()
does.

There is also an unlocked read of cfs_b->runtime_expires, but a race
there would only delay runtime expiry by a tick. Still, the comparison
should just be != anyway, which clarifies even that problem.

Signed-off-by: Ben Segall <bsegall@google.com>
Tested-by: Roman Gushchin <klamm@yandex-team.ru>
[peterz: Fix compile warn]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140519224945.20303.93530.stgit@sword-of-the-dawn.mtv.corp.google.com
Cc: pjt@google.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05 11:52:00 +02:00
..
auto_group.c sched: Replace hardcoding of -20 and 19 with MIN_NICE and MAX_NICE 2014-02-22 18:15:54 +01:00
auto_group.h Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled" 2012-12-11 10:23:45 +01:00
clock.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
completion.c sched: Move completion code from core.c to completion.c 2013-11-06 07:49:19 +01:00
core.c sched: Consolidate open coded implementations of nice level frobbing into nice_to_rlimit() and rlimit_to_nice() 2014-05-22 11:16:36 +02:00
cpuacct.c cgroup: clean up cgroup_subsys names and initialization 2014-02-08 10:36:58 -05:00
cpuacct.h sched/cpuacct: Initialize root cpuacct earlier 2013-04-10 13:54:20 +02:00
cpudeadline.c sched/deadline: Replace NR_CPUS arrays 2014-05-22 10:21:28 +02:00
cpudeadline.h sched/deadline: Replace NR_CPUS arrays 2014-05-22 10:21:28 +02:00
cpupri.c sched/cpupri: Replace NR_CPUS arrays 2014-05-22 10:21:29 +02:00
cpupri.h sched/cpupri: Replace NR_CPUS arrays 2014-05-22 10:21:29 +02:00
cputime.c sched: Sanitize irq accounting madness 2014-05-07 11:51:30 +02:00
deadline.c sched/rt: Fix 'struct sched_dl_entity' and dl_task_time() comments, to match the current upstream code 2014-05-22 11:16:37 +02:00
debug.c Merge branch 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-04-03 13:05:42 -07:00
fair.c sched/fair: Fix unlocked reads of some cfs_b->quota/period 2014-06-05 11:52:00 +02:00
features.h sched/numa: Resist moving tasks towards nodes with fewer hinting faults 2013-10-09 12:40:27 +02:00
idle_task.c sched/fair: Push down check for high priority class task into idle_balance() 2014-03-11 12:05:37 +01:00
idle.c Merge branch 'pm-cpuidle' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm into sched/core 2014-05-22 10:37:06 +02:00
Makefile sched/idle: Move cpu/idle.c to sched/idle.c 2014-02-11 09:58:30 +01:00
proc.c sched: Change get_rq_runnable_load() to static and inline 2013-06-27 10:07:44 +02:00
rt.c sched, nohz: Change rq->nr_running to always use wrappers 2014-05-22 11:16:33 +02:00
sched.h sched, nohz: Change rq->nr_running to always use wrappers 2014-05-22 11:16:33 +02:00
stats.c kernel: audit/fix non-modular users of module_init in core code 2014-04-03 16:21:07 -07:00
stats.h sched: Micro-optimize by dropping unnecessary task_rq() calls 2013-09-25 13:51:06 +02:00
stop_task.c sched, nohz: Change rq->nr_running to always use wrappers 2014-05-22 11:16:33 +02:00
wait.c sched: Move wait code from core.c to wait.c 2013-11-06 07:49:18 +01:00