futex: Fix uninterruptible loop due to gate_area

[linux-2.6.git] / kernel / pid_namespace.c

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 598f1eec9826a929e40f142b3dffe1a69d8d28e9..e9c9adc84ca6e50f5f457e081bb45c36b35bf4d1 100644 (file)
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -13,6 +13,8 @@
 #include <linux/syscalls.h>
 #include <linux/err.h>
 #include <linux/acct.h>
+#include <linux/slab.h>
+#include <linux/proc_fs.h>
 
 #define BITS_PER_PAGE          (PAGE_SIZE*8)
 
@@ -67,10 +69,11 @@ err_alloc:
        return NULL;
 }
 
-static struct pid_namespace *create_pid_namespace(unsigned int level)
+static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns)
 {
        struct pid_namespace *ns;
-       int i;
+       unsigned int level = parent_pid_ns->level + 1;
+       int i, err = -ENOMEM;
 
        ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
        if (ns == NULL)
@@ -86,6 +89,7 @@ static struct pid_namespace *create_pid_namespace(unsigned int level)
 
        kref_init(&ns->kref);
        ns->level = level;
+       ns->parent = get_pid_ns(parent_pid_ns);
 
        set_bit(0, ns->pidmap[0].page);
        atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
@@ -93,14 +97,20 @@ static struct pid_namespace *create_pid_namespace(unsigned int level)
        for (i = 1; i < PIDMAP_ENTRIES; i++)
                atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
 
+       err = pid_ns_prepare_proc(ns);
+       if (err)
+               goto out_put_parent_pid_ns;
+
        return ns;
 
+out_put_parent_pid_ns:
+       put_pid_ns(parent_pid_ns);
 out_free_map:
        kfree(ns->pidmap[0].page);
 out_free:
        kmem_cache_free(pid_ns_cachep, ns);
 out:
-       return ERR_PTR(-ENOMEM);
+       return ERR_PTR(err);
 }
 
 static void destroy_pid_namespace(struct pid_namespace *ns)
@@ -114,25 +124,11 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
 
 struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
 {
-       struct pid_namespace *new_ns;
-
-       BUG_ON(!old_ns);
-       new_ns = get_pid_ns(old_ns);
        if (!(flags & CLONE_NEWPID))
-               goto out;
-
-       new_ns = ERR_PTR(-EINVAL);
-       if (flags & CLONE_THREAD)
-               goto out_put;
-
-       new_ns = create_pid_namespace(old_ns->level + 1);
-       if (!IS_ERR(new_ns))
-               new_ns->parent = get_pid_ns(old_ns);
-
-out_put:
-       put_pid_ns(old_ns);
-out:
-       return new_ns;
+               return get_pid_ns(old_ns);
+       if (flags & (CLONE_THREAD|CLONE_PARENT))
+               return ERR_PTR(-EINVAL);
+       return create_pid_namespace(old_ns);
 }
 
 void free_pid_ns(struct kref *kref)
@@ -152,6 +148,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 {
        int nr;
        int rc;
+       struct task_struct *task;
 
        /*
         * The last thread in the cgroup-init thread group is terminating.
@@ -169,7 +166,18 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
        read_lock(&tasklist_lock);
        nr = next_pidmap(pid_ns, 1);
        while (nr > 0) {
-               kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
+               rcu_read_lock();
+
+               /*
+                * Any nested-container's init processes won't ignore the
+                * SEND_SIG_NOINFO signal, see send_signal()->si_fromuser().
+                */
+               task = pid_task(find_vpid(nr), PIDTYPE_PID);
+               if (task)
+                       send_sig_info(SIGKILL, SEND_SIG_NOINFO, task);
+
+               rcu_read_unlock();
+
                nr = next_pidmap(pid_ns, nr);
        }
        read_unlock(&tasklist_lock);
@@ -179,12 +187,6 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
                rc = sys_wait4(-1, NULL, __WALL, NULL);
        } while (rc != -ECHILD);
 
-       /*
-        * We can not clear ->child_reaper or leave it alone.
-        * There may by stealth EXIT_DEAD tasks on ->children,
-        * forget_original_parent() must move them somewhere.
-        */
-       pid_ns->child_reaper = init_pid_ns.child_reaper;
        acct_exit_ns(pid_ns);
        return;
 }