signals: zap_pid_ns_process() should use force_sig()
[linux-2.6.git] / kernel / pid_namespace.c
index 98702b4..2d1001b 100644 (file)
@@ -12,6 +12,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/syscalls.h>
 #include <linux/err.h>
+#include <linux/acct.h>
 
 #define BITS_PER_PAGE          (PAGE_SIZE*8)
 
@@ -71,7 +72,7 @@ static struct pid_namespace *create_pid_namespace(unsigned int level)
        struct pid_namespace *ns;
        int i;
 
-       ns = kmem_cache_alloc(pid_ns_cachep, GFP_KERNEL);
+       ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
        if (ns == NULL)
                goto out;
 
@@ -84,17 +85,13 @@ static struct pid_namespace *create_pid_namespace(unsigned int level)
                goto out_free_map;
 
        kref_init(&ns->kref);
-       ns->last_pid = 0;
-       ns->child_reaper = NULL;
        ns->level = level;
 
        set_bit(0, ns->pidmap[0].page);
        atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
 
-       for (i = 1; i < PIDMAP_ENTRIES; i++) {
-               ns->pidmap[i].page = NULL;
+       for (i = 1; i < PIDMAP_ENTRIES; i++)
                atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
-       }
 
        return ns;
 
@@ -155,6 +152,7 @@ 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.
@@ -172,7 +170,19 @@ 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();
+
+               /*
+                * Use force_sig() since it clears SIGNAL_UNKILLABLE ensuring
+                * any nested-container's init processes don't ignore the
+                * signal
+                */
+               task = pid_task(find_vpid(nr), PIDTYPE_PID);
+               if (task)
+                       force_sig(SIGKILL, task);
+
+               rcu_read_unlock();
+
                nr = next_pidmap(pid_ns, nr);
        }
        read_unlock(&tasklist_lock);
@@ -182,9 +192,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
                rc = sys_wait4(-1, NULL, __WALL, NULL);
        } while (rc != -ECHILD);
 
-
-       /* Child reaper for the pid namespace is going away */
-       pid_ns->child_reaper = NULL;
+       acct_exit_ns(pid_ns);
        return;
 }