/* SLAB cache for mm_struct structures (tsk->mm) */
static struct kmem_cache *mm_cachep;
+/* Notifier list called when a task struct is freed */
+static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
+
static void account_kernel_stack(struct thread_info *ti, int account)
{
struct zone *zone = page_zone(virt_to_page(ti));
free_signal_struct(sig);
}
+int task_free_register(struct notifier_block *n)
+{
+ return atomic_notifier_chain_register(&task_free_notifier, n);
+}
+EXPORT_SYMBOL(task_free_register);
+
+int task_free_unregister(struct notifier_block *n)
+{
+ return atomic_notifier_chain_unregister(&task_free_notifier, n);
+}
+EXPORT_SYMBOL(task_free_unregister);
+
void __put_task_struct(struct task_struct *tsk)
{
WARN_ON(!tsk->exit_state);
delayacct_tsk_free(tsk);
put_signal_struct(tsk->signal);
+ atomic_notifier_call_chain(&task_free_notifier, 0, tsk);
if (!profile_handoff_task(tsk))
free_task(tsk);
}
goto free_ti;
tsk->stack = ti;
+#ifdef CONFIG_SECCOMP
+ /*
+ * We must handle setting up seccomp filters once we're under
+ * the sighand lock in case orig has changed between now and
+ * then. Until then, filter must be NULL to avoid messing up
+ * the usage counts on the error path calling free_task.
+ */
+ tsk->seccomp.filter = NULL;
+#endif
setup_thread_stack(tsk, orig);
clear_user_return_notifier(tsk);
mm = get_task_mm(task);
if (mm && mm != current->mm &&
- !ptrace_may_access(task, mode)) {
+ !ptrace_may_access(task, mode) &&
+ !capable(CAP_SYS_RESOURCE)) {
mmput(mm);
mm = ERR_PTR(-EACCES);
}
sig->nr_threads = 1;
atomic_set(&sig->live, 1);
atomic_set(&sig->sigcnt, 1);
+
+ /* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
+ sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
+ tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head);
+
init_waitqueue_head(&sig->wait_chldexit);
sig->curr_target = tsk;
init_sigpending(&sig->shared_pending);
p->flags = new_flags;
}
+static void copy_seccomp(struct task_struct *p)
+{
+#ifdef CONFIG_SECCOMP
+ /*
+ * Must be called with sighand->lock held, which is common to
+ * all threads in the group. Holding cred_guard_mutex is not
+ * needed because this new task is not yet running and cannot
+ * be racing exec.
+ */
+ assert_spin_locked(¤t->sighand->siglock);
+
+ /* Ref-count the new filter user, and assign it. */
+ get_seccomp_filter(current);
+ p->seccomp = current->seccomp;
+
+ /*
+ * Explicitly enable no_new_privs here in case it got set
+ * between the task_struct being duplicated and holding the
+ * sighand lock. The seccomp state and nnp must be in sync.
+ */
+ if (task_no_new_privs(current))
+ task_set_no_new_privs(p);
+
+ /*
+ * If the parent gained a seccomp mode after copying thread
+ * flags and between before we held the sighand lock, we have
+ * to manually enable the seccomp thread flag here.
+ */
+ if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
+ set_tsk_thread_flag(p, TIF_SECCOMP);
+#endif
+}
+
SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
{
current->clear_child_tid = tidptr;
goto fork_out;
ftrace_graph_init_task(p);
- get_seccomp_filter(p);
rt_mutex_init_task(p);
goto bad_fork_cleanup_policy;
retval = audit_alloc(p);
if (retval)
- goto bad_fork_cleanup_policy;
+ goto bad_fork_cleanup_perf;
/* copy all the process information */
retval = copy_semundo(clone_flags, p);
if (retval)
spin_lock(¤t->sighand->siglock);
+ /*
+ * Copy seccomp details explicitly here, in case they were changed
+ * before holding sighand lock.
+ */
+ copy_seccomp(p);
+
/*
* Process group and session signals need to be delivered to just the
* parent before the fork or both the parent and the child after the
goto bad_fork_free_pid;
}
- if (clone_flags & CLONE_THREAD) {
- current->signal->nr_threads++;
- atomic_inc(¤t->signal->live);
- atomic_inc(¤t->signal->sigcnt);
- p->group_leader = current->group_leader;
- list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
- }
-
if (likely(p->pid)) {
ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
list_add_tail(&p->sibling, &p->real_parent->children);
list_add_tail_rcu(&p->tasks, &init_task.tasks);
__this_cpu_inc(process_counts);
+ } else {
+ current->signal->nr_threads++;
+ atomic_inc(¤t->signal->live);
+ atomic_inc(¤t->signal->sigcnt);
+ p->group_leader = current->group_leader;
+ list_add_tail_rcu(&p->thread_group,
+ &p->group_leader->thread_group);
+ list_add_tail_rcu(&p->thread_node,
+ &p->signal->thread_head);
}
attach_pid(p, PIDTYPE_PID, pid);
nr_threads++;
exit_sem(p);
bad_fork_cleanup_audit:
audit_free(p);
-bad_fork_cleanup_policy:
+bad_fork_cleanup_perf:
perf_event_free_task(p);
+bad_fork_cleanup_policy:
#ifdef CONFIG_NUMA
mpol_put(p->mempolicy);
bad_fork_cleanup_cgroup: