diff options
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 50 |
1 files changed, 32 insertions, 18 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 40e3af12c55e..03aa2e6de7a4 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -287,6 +287,11 @@ static void set_max_threads(unsigned int max_threads_suggested) max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS); } +#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT +/* Initialized by the architecture: */ +int arch_task_struct_size __read_mostly; +#endif + void __init fork_init(void) { #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR @@ -295,7 +300,7 @@ void __init fork_init(void) #endif /* create a slab on which task_structs can be allocated */ task_struct_cachep = - kmem_cache_create("task_struct", sizeof(struct task_struct), + kmem_cache_create("task_struct", arch_task_struct_size, ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL); #endif @@ -1067,6 +1072,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) rcu_assign_pointer(tsk->sighand, sig); if (!sig) return -ENOMEM; + atomic_set(&sig->count, 1); memcpy(sig->action, current->sighand->action, sizeof(sig->action)); return 0; @@ -1128,6 +1134,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) init_sigpending(&sig->shared_pending); INIT_LIST_HEAD(&sig->posix_timers); seqlock_init(&sig->stats_lock); + prev_cputime_init(&sig->prev_cputime); hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); sig->real_timer.function = it_real_fn; @@ -1274,10 +1281,9 @@ static struct task_struct *copy_process(unsigned long clone_flags, /* * If the new process will be in a different pid or user namespace - * do not allow it to share a thread group or signal handlers or - * parent with the forking task. + * do not allow it to share a thread group with the forking task. */ - if (clone_flags & CLONE_SIGHAND) { + if (clone_flags & CLONE_THREAD) { if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) || (task_active_pid_ns(current) != current->nsproxy->pid_ns_for_children)) @@ -1336,9 +1342,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->utime = p->stime = p->gtime = 0; p->utimescaled = p->stimescaled = 0; -#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE - p->prev_cputime.utime = p->prev_cputime.stime = 0; -#endif + prev_cputime_init(&p->prev_cputime); + #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN seqlock_init(&p->vtime_seqlock); p->vtime_snap = 0; @@ -1879,13 +1884,21 @@ static int check_unshare_flags(unsigned long unshare_flags) CLONE_NEWUSER|CLONE_NEWPID)) return -EINVAL; /* - * Not implemented, but pretend it works if there is nothing to - * unshare. Note that unsharing CLONE_THREAD or CLONE_SIGHAND - * needs to unshare vm. + * Not implemented, but pretend it works if there is nothing + * to unshare. Note that unsharing the address space or the + * signal handlers also need to unshare the signal queues (aka + * CLONE_THREAD). */ if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) { - /* FIXME: get_task_mm() increments ->mm_users */ - if (atomic_read(¤t->mm->mm_users) > 1) + if (!thread_group_empty(current)) + return -EINVAL; + } + if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) { + if (atomic_read(¤t->sighand->count) > 1) + return -EINVAL; + } + if (unshare_flags & CLONE_VM) { + if (!current_is_single_threaded()) return -EINVAL; } @@ -1949,21 +1962,22 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) int err; /* - * If unsharing a user namespace must also unshare the thread. + * If unsharing a user namespace must also unshare the thread group + * and unshare the filesystem root and working directories. */ if (unshare_flags & CLONE_NEWUSER) unshare_flags |= CLONE_THREAD | CLONE_FS; /* - * If unsharing a thread from a thread group, must also unshare vm. - */ - if (unshare_flags & CLONE_THREAD) - unshare_flags |= CLONE_VM; - /* * If unsharing vm, must also unshare signal handlers. */ if (unshare_flags & CLONE_VM) unshare_flags |= CLONE_SIGHAND; /* + * If unsharing a signal handlers, must also unshare the signal queues. + */ + if (unshare_flags & CLONE_SIGHAND) + unshare_flags |= CLONE_THREAD; + /* * If unsharing namespace, must also unshare filesystem information. */ if (unshare_flags & CLONE_NEWNS) |