[PATCH] disable unshare(CLONE_VM) for now

[linux-2.6-omap-h63xx.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 8e88b374cee90b646234d7cfa64b108c8ab9bbe2..b373322ca4977a632bed40a38de125e9db482228 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -108,8 +108,10 @@ void free_task(struct task_struct *tsk)
 }
 EXPORT_SYMBOL(free_task);
 
-void __put_task_struct(struct task_struct *tsk)
+void __put_task_struct_cb(struct rcu_head *rhp)
 {
+       struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+
        WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)));
        WARN_ON(atomic_read(&tsk->usage));
        WARN_ON(tsk == current);
@@ -1059,6 +1061,12 @@ static task_t *copy_process(unsigned long clone_flags,
         */
        p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
 
+       /*
+        * sigaltstack should be cleared when sharing the same VM
+        */
+       if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
+               p->sas_ss_sp = p->sas_ss_size = 0;
+
        /*
         * Syscall tracing should be turned off in the child regardless
         * of CLONE_PTRACE.
@@ -1123,8 +1131,8 @@ static task_t *copy_process(unsigned long clone_flags,
                p->real_parent = current;
        p->parent = p->real_parent;
 
+       spin_lock(&current->sighand->siglock);
        if (clone_flags & CLONE_THREAD) {
-               spin_lock(&current->sighand->siglock);
                /*
                 * Important: if an exit-all has been started then
                 * do not create this new thread - the whole thread
@@ -1162,8 +1170,6 @@ static task_t *copy_process(unsigned long clone_flags,
                         */
                        p->it_prof_expires = jiffies_to_cputime(1);
                }
-
-               spin_unlock(&current->sighand->siglock);
        }
 
        /*
@@ -1175,8 +1181,6 @@ static task_t *copy_process(unsigned long clone_flags,
        if (unlikely(p->ptrace & PT_PTRACED))
                __ptrace_link(p, current->parent);
 
-       attach_pid(p, PIDTYPE_PID, p->pid);
-       attach_pid(p, PIDTYPE_TGID, p->tgid);
        if (thread_group_leader(p)) {
                p->signal->tty = current->signal->tty;
                p->signal->pgrp = process_group(current);
@@ -1186,9 +1190,12 @@ static task_t *copy_process(unsigned long clone_flags,
                if (p->pid)
                        __get_cpu_var(process_counts)++;
        }
+       attach_pid(p, PIDTYPE_TGID, p->tgid);
+       attach_pid(p, PIDTYPE_PID, p->pid);
 
        nr_threads++;
        total_forks++;
+       spin_unlock(&current->sighand->siglock);
        write_unlock_irq(&tasklist_lock);
        proc_fork_connector(p);
        return p;
@@ -1471,9 +1478,7 @@ static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp)
 
        if ((unshare_flags & CLONE_VM) &&
            (mm && atomic_read(&mm->mm_users) > 1)) {
-               *new_mmp = dup_mm(current);
-               if (!*new_mmp)
-                       return -ENOMEM;
+               return -EINVAL;
        }
 
        return 0;
@@ -1562,7 +1567,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
 
                if (new_sigh) {
                        sigh = current->sighand;
-                       current->sighand = new_sigh;
+                       rcu_assign_pointer(current->sighand, new_sigh);
                        new_sigh = sigh;
                }