diff options
| -rw-r--r-- | include/linux/init_task.h | 9 | ||||
| -rw-r--r-- | include/linux/sched.h | 36 | ||||
| -rw-r--r-- | kernel/fork.c | 10 |
3 files changed, 55 insertions, 0 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h index bafc58c00fc3..580f70c02391 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -22,6 +22,14 @@ extern struct files_struct init_files; extern struct fs_struct init_fs; +#ifdef CONFIG_CGROUPS +#define INIT_THREADGROUP_FORK_LOCK(sig) \ + .threadgroup_fork_lock = \ + __RWSEM_INITIALIZER(sig.threadgroup_fork_lock), +#else +#define INIT_THREADGROUP_FORK_LOCK(sig) +#endif + #define INIT_SIGNALS(sig) { \ .nr_threads = 1, \ .wait_chldexit = __WAIT_QUEUE_HEAD_INITIALIZER(sig.wait_chldexit),\ @@ -38,6 +46,7 @@ extern struct fs_struct init_fs; }, \ .cred_guard_mutex = \ __MUTEX_INITIALIZER(sig.cred_guard_mutex), \ + INIT_THREADGROUP_FORK_LOCK(sig) \ } extern struct nsproxy init_nsproxy; diff --git a/include/linux/sched.h b/include/linux/sched.h index f18300eddfcb..dc8871295a5a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -513,6 +513,7 @@ struct thread_group_cputimer { spinlock_t lock; }; +#include <linux/rwsem.h> struct autogroup; /* @@ -632,6 +633,16 @@ struct signal_struct { unsigned audit_tty; struct tty_audit_buf *tty_audit_buf; #endif +#ifdef CONFIG_CGROUPS + /* + * The threadgroup_fork_lock prevents threads from forking with + * CLONE_THREAD while held for writing. Use this for fork-sensitive + * threadgroup-wide operations. It's taken for reading in fork.c in + * copy_process(). + * Currently only needed write-side by cgroups. + */ + struct rw_semaphore threadgroup_fork_lock; +#endif int oom_adj; /* OOM kill score adjustment (bit shift) */ int oom_score_adj; /* OOM kill score adjustment */ @@ -2323,6 +2334,31 @@ static inline void unlock_task_sighand(struct task_struct *tsk, spin_unlock_irqrestore(&tsk->sighand->siglock, *flags); } +/* See the declaration of threadgroup_fork_lock in signal_struct. */ +#ifdef CONFIG_CGROUPS +static inline void threadgroup_fork_read_lock(struct task_struct *tsk) +{ + down_read(&tsk->signal->threadgroup_fork_lock); +} +static inline void threadgroup_fork_read_unlock(struct task_struct *tsk) +{ + up_read(&tsk->signal->threadgroup_fork_lock); +} +static inline void threadgroup_fork_write_lock(struct task_struct *tsk) +{ + down_write(&tsk->signal->threadgroup_fork_lock); +} +static inline void threadgroup_fork_write_unlock(struct task_struct *tsk) +{ + up_write(&tsk->signal->threadgroup_fork_lock); +} +#else +static inline void threadgroup_fork_read_lock(struct task_struct *tsk) {} +static inline void threadgroup_fork_read_unlock(struct task_struct *tsk) {} +static inline void threadgroup_fork_write_lock(struct task_struct *tsk) {} +static inline void threadgroup_fork_write_unlock(struct task_struct *tsk) {} +#endif + #ifndef __HAVE_THREAD_FUNCTIONS #define task_thread_info(task) ((struct thread_info *)(task)->stack) diff --git a/kernel/fork.c b/kernel/fork.c index 8e7e135d0817..1fa9d940e301 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -957,6 +957,10 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) tty_audit_fork(sig); sched_autogroup_fork(sig); +#ifdef CONFIG_CGROUPS + init_rwsem(&sig->threadgroup_fork_lock); +#endif + sig->oom_adj = current->signal->oom_adj; sig->oom_score_adj = current->signal->oom_score_adj; sig->oom_score_adj_min = current->signal->oom_score_adj_min; @@ -1138,6 +1142,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, monotonic_to_bootbased(&p->real_start_time); p->io_context = NULL; p->audit_context = NULL; + if (clone_flags & CLONE_THREAD) + threadgroup_fork_read_lock(current); cgroup_fork(p); #ifdef CONFIG_NUMA p->mempolicy = mpol_dup(p->mempolicy); @@ -1342,6 +1348,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, write_unlock_irq(&tasklist_lock); proc_fork_connector(p); cgroup_post_fork(p); + if (clone_flags & CLONE_THREAD) + threadgroup_fork_read_unlock(current); perf_event_fork(p); return p; @@ -1380,6 +1388,8 @@ bad_fork_cleanup_policy: mpol_put(p->mempolicy); bad_fork_cleanup_cgroup: #endif + if (clone_flags & CLONE_THREAD) + threadgroup_fork_read_unlock(current); cgroup_exit(p, cgroup_callbacks_done); delayacct_tsk_free(p); module_put(task_thread_info(p)->exec_domain->module); |