diff options
| author | Juri Lelli <[email protected]> | 2019-07-19 16:00:00 +0200 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2019-07-25 15:55:04 +0200 |
| commit | 710da3c8ea7dfbd327920afd3831d8c82c42789d (patch) | |
| tree | 146d69299e74b9c9fe0e23a0588484543ccec8f1 /include/linux | |
| parent | 1a763fd7c6335e3122c1cc09576ef6c99ada4267 (diff) | |
sched/core: Prevent race condition between cpuset and __sched_setscheduler()
No synchronisation mechanism exists between the cpuset subsystem and
calls to function __sched_setscheduler(). As such, it is possible that
new root domains are created on the cpuset side while a deadline
acceptance test is carried out in __sched_setscheduler(), leading to a
potential oversell of CPU bandwidth.
Grab cpuset_rwsem read lock from core scheduler, so to prevent
situations such as the one described above from happening.
The only exception is normalize_rt_tasks() which needs to work under
tasklist_lock and can't therefore grab cpuset_rwsem. We are fine with
this, as this function is only called by sysrq and, if that gets
triggered, DEADLINE guarantees are already gone out of the window
anyway.
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Juri Lelli <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/cpuset.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index 7f1478c26a33..04c20de66afc 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -55,6 +55,8 @@ extern void cpuset_init_smp(void); extern void cpuset_force_rebuild(void); extern void cpuset_update_active_cpus(void); extern void cpuset_wait_for_hotplug(void); +extern void cpuset_read_lock(void); +extern void cpuset_read_unlock(void); extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); extern void cpuset_cpus_allowed_fallback(struct task_struct *p); extern nodemask_t cpuset_mems_allowed(struct task_struct *p); @@ -176,6 +178,9 @@ static inline void cpuset_update_active_cpus(void) static inline void cpuset_wait_for_hotplug(void) { } +static inline void cpuset_read_lock(void) { } +static inline void cpuset_read_unlock(void) { } + static inline void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask) { |