diff options
author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-04-28 11:33:07 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-05-05 23:56:18 +0200 |
commit | 712555ee4f873515612f89554ad1a3fda5fa887e (patch) | |
tree | 88ff7222727c63959eb58a3aa729029aaf08a64f /kernel/sched.c | |
parent | sched: make clock sync tunable by architecture code (diff) | |
download | linux-712555ee4f873515612f89554ad1a3fda5fa887e.tar.xz linux-712555ee4f873515612f89554ad1a3fda5fa887e.zip |
sched: fix missing locking in sched_domains code
Concurrent calls to detach_destroy_domains and arch_init_sched_domains
were prevented by the old scheduler subsystem cpu hotplug mutex. When
this got converted to get_online_cpus() the locking got broken.
Unlike before now several processes can concurrently enter the critical
sections that were protected by the old lock.
So use the already present doms_cur_mutex to protect these sections again.
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 29 |
1 files changed, 12 insertions, 17 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 8f433fedfcb3..561b3b39bdb8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -242,6 +242,12 @@ static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b) } #endif +/* + * sched_domains_mutex serializes calls to arch_init_sched_domains, + * detach_destroy_domains and partition_sched_domains. + */ +static DEFINE_MUTEX(sched_domains_mutex); + #ifdef CONFIG_GROUP_SCHED #include <linux/cgroup.h> @@ -308,9 +314,6 @@ static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp; */ static DEFINE_SPINLOCK(task_group_lock); -/* doms_cur_mutex serializes access to doms_cur[] array */ -static DEFINE_MUTEX(doms_cur_mutex); - #ifdef CONFIG_FAIR_GROUP_SCHED #ifdef CONFIG_USER_SCHED # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD) @@ -358,21 +361,9 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu) #endif } -static inline void lock_doms_cur(void) -{ - mutex_lock(&doms_cur_mutex); -} - -static inline void unlock_doms_cur(void) -{ - mutex_unlock(&doms_cur_mutex); -} - #else static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } -static inline void lock_doms_cur(void) { } -static inline void unlock_doms_cur(void) { } #endif /* CONFIG_GROUP_SCHED */ @@ -7822,7 +7813,7 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new, { int i, j; - lock_doms_cur(); + mutex_lock(&sched_domains_mutex); /* always unregister in case we don't destroy any domains */ unregister_sched_domain_sysctl(); @@ -7871,7 +7862,7 @@ match2: register_sched_domain_sysctl(); - unlock_doms_cur(); + mutex_unlock(&sched_domains_mutex); } #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) @@ -7880,8 +7871,10 @@ int arch_reinit_sched_domains(void) int err; get_online_cpus(); + mutex_lock(&sched_domains_mutex); detach_destroy_domains(&cpu_online_map); err = arch_init_sched_domains(&cpu_online_map); + mutex_unlock(&sched_domains_mutex); put_online_cpus(); return err; @@ -7999,10 +7992,12 @@ void __init sched_init_smp(void) BUG_ON(sched_group_nodes_bycpu == NULL); #endif get_online_cpus(); + mutex_lock(&sched_domains_mutex); arch_init_sched_domains(&cpu_online_map); cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); if (cpus_empty(non_isolated_cpus)) cpu_set(smp_processor_id(), non_isolated_cpus); + mutex_unlock(&sched_domains_mutex); put_online_cpus(); /* XXX: Theoretical race here - CPU may be hotplugged now */ hotcpu_notifier(update_sched_domains, 0); |