diff options
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 70 |
1 files changed, 49 insertions, 21 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 1bfefc6f96a4..7d5f0f118a63 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 @@ -449,8 +454,9 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) tmp->vm_mm = mm; if (anon_vma_fork(tmp, mpnt)) goto fail_nomem_anon_vma_fork; - tmp->vm_flags &= ~VM_LOCKED; + tmp->vm_flags &= ~(VM_LOCKED|VM_UFFD_MISSING|VM_UFFD_WP); tmp->vm_next = tmp->vm_prev = NULL; + tmp->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX; file = tmp->vm_file; if (file) { struct inode *inode = file_inode(file); @@ -1067,6 +1073,7 @@ 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 +1135,7 @@ 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; @@ -1239,6 +1247,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, { int retval; struct task_struct *p; + void *cgrp_ss_priv[CGROUP_CANFORK_COUNT] = {}; if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) return ERR_PTR(-EINVAL); @@ -1273,10 +1282,9 @@ 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)) @@ -1335,9 +1343,8 @@ 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; @@ -1513,6 +1520,16 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->task_works = NULL; /* + * Ensure that the cgroup subsystem policies allow the new process to be + * forked. It should be noted the the new process's css_set can be changed + * between here and cgroup_post_fork() if an organisation operation is in + * progress. + */ + retval = cgroup_can_fork(p, cgrp_ss_priv); + if (retval) + goto bad_fork_free_pid; + + /* * Make it visible to the rest of the system, but dont wake it up yet. * Need tasklist lock for parent etc handling! */ @@ -1548,7 +1565,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, spin_unlock(¤t->sighand->siglock); write_unlock_irq(&tasklist_lock); retval = -ERESTARTNOINTR; - goto bad_fork_free_pid; + goto bad_fork_cancel_cgroup; } if (likely(p->pid)) { @@ -1590,7 +1607,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, write_unlock_irq(&tasklist_lock); proc_fork_connector(p); - cgroup_post_fork(p); + cgroup_post_fork(p, cgrp_ss_priv); if (clone_flags & CLONE_THREAD) threadgroup_change_end(current); perf_event_fork(p); @@ -1600,6 +1617,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, return p; +bad_fork_cancel_cgroup: + cgroup_cancel_fork(p, cgrp_ss_priv); bad_fork_free_pid: if (pid != &init_struct_pid) free_pid(pid); @@ -1866,13 +1885,21 @@ 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; } @@ -1936,21 +1963,22 @@ 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) |