locking/spinlock/debug: Fix various data races

[platform/kernel/linux-rpi.git] / kernel / exit.c

diff --git a/kernel/exit.c b/kernel/exit.c
index 0e21e6d..54c3269 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -194,6 +194,7 @@ repeat:
        rcu_read_unlock();
 
        proc_flush_task(p);
+       cgroup_release(p);
 
        write_lock_irq(&tasklist_lock);
        ptrace_release_task(p);
@@ -307,7 +308,7 @@ void rcuwait_wake_up(struct rcuwait *w)
         *        MB (A)              MB (B)
         *    [L] cond            [L] tsk
         */
-       smp_rmb(); /* (B) */
+       smp_mb(); /* (B) */
 
        /*
         * Avoid using task_rcu_dereference() magic as long as we are careful,
@@ -558,12 +559,14 @@ static struct task_struct *find_alive_thread(struct task_struct *p)
        return NULL;
 }
 
-static struct task_struct *find_child_reaper(struct task_struct *father)
+static struct task_struct *find_child_reaper(struct task_struct *father,
+                                               struct list_head *dead)
        __releases(&tasklist_lock)
        __acquires(&tasklist_lock)
 {
        struct pid_namespace *pid_ns = task_active_pid_ns(father);
        struct task_struct *reaper = pid_ns->child_reaper;
+       struct task_struct *p, *n;
 
        if (likely(reaper != father))
                return reaper;
@@ -575,10 +578,12 @@ static struct task_struct *find_child_reaper(struct task_struct *father)
        }
 
        write_unlock_irq(&tasklist_lock);
-       if (unlikely(pid_ns == &init_pid_ns)) {
-               panic("Attempted to kill init! exitcode=0x%08x\n",
-                       father->signal->group_exit_code ?: father->exit_code);
+
+       list_for_each_entry_safe(p, n, dead, ptrace_entry) {
+               list_del_init(&p->ptrace_entry);
+               release_task(p);
        }
+
        zap_pid_ns_processes(pid_ns);
        write_lock_irq(&tasklist_lock);
 
@@ -668,7 +673,7 @@ static void forget_original_parent(struct task_struct *father,
                exit_ptrace(father, dead);
 
        /* Can drop and reacquire tasklist_lock */
-       reaper = find_child_reaper(father);
+       reaper = find_child_reaper(father, dead);
        if (list_empty(&father->children))
                return;
 
@@ -836,6 +841,14 @@ void __noreturn do_exit(long code)
        acct_update_integrals(tsk);
        group_dead = atomic_dec_and_test(&tsk->signal->live);
        if (group_dead) {
+               /*
+                * If the last thread of global init has exited, panic
+                * immediately to get a useable coredump.
+                */
+               if (unlikely(is_global_init(tsk)))
+                       panic("Attempted to kill init! exitcode=0x%08x\n",
+                               tsk->signal->group_exit_code ?: (int)code);
+
 #ifdef CONFIG_POSIX_TIMERS
                hrtimer_cancel(&tsk->signal->real_timer);
                exit_itimers(tsk->signal);