linux 2.6.16.38 w/ vs2.0.3-rc1
[linux-2.6.git] / kernel / exit.c
index a3c5997..208cbfa 100644 (file)
@@ -10,6 +10,7 @@
 #include <linux/interrupt.h>
 #include <linux/smp_lock.h>
 #include <linux/module.h>
+#include <linux/capability.h>
 #include <linux/completion.h>
 #include <linux/personality.h>
 #include <linux/tty.h>
 #include <linux/mount.h>
 #include <linux/proc_fs.h>
 #include <linux/mempolicy.h>
-#include <linux/ckrm.h>
-#include <linux/ckrm_tsk.h>
-#include <linux/ckrm_mem_inline.h>
+#include <linux/cpuset.h>
 #include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/cn_proc.h>
+#include <linux/mutex.h>
 #include <linux/vs_limit.h>
+#include <linux/vs_context.h>
+#include <linux/vs_network.h>
+#include <linux/vs_cvirt.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -41,14 +46,11 @@ extern struct task_struct *child_reaper;
 
 int getrusage(struct task_struct *, int, struct rusage __user *);
 
+static void exit_mm(struct task_struct * tsk);
+
 static void __unhash_process(struct task_struct *p)
 {
        nr_threads--;
-       /* tasklist_lock is held, is this sufficient? */
-       if (p->vx_info) {
-               atomic_dec(&p->vx_info->cvirt.nr_threads);
-               vx_nproc_dec(p);
-       }
        detach_pid(p, PIDTYPE_PID);
        detach_pid(p, PIDTYPE_TGID);
        if (thread_group_leader(p)) {
@@ -76,7 +78,11 @@ repeat:
                __ptrace_unlink(p);
        BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
        __exit_signal(p);
-       __exit_sighand(p);
+       /*
+        * Note that the fastpath in sys_times depends on __exit_signal having
+        * updated the counters before a task is removed from the tasklist of
+        * the process by __unhash_process.
+        */
        __unhash_process(p);
 
        /*
@@ -168,7 +174,7 @@ static int will_become_orphaned_pgrp(int pgrp, task_t *ignored_task)
 
        do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
                if (p == ignored_task
-                               || p->exit_state >= EXIT_ZOMBIE
+                               || p->exit_state
                                || p->real_parent->pid == 1)
                        continue;
                if (process_group(p->real_parent) != pgrp
@@ -191,7 +197,7 @@ int is_orphaned_pgrp(int pgrp)
        return retval;
 }
 
-static inline int has_stopped_jobs(int pgrp)
+static int has_stopped_jobs(int pgrp)
 {
        int retval = 0;
        struct task_struct *p;
@@ -217,7 +223,7 @@ static inline int has_stopped_jobs(int pgrp)
 }
 
 /**
- * reparent_to_init() - Reparent the calling kernel thread to the init task.
+ * reparent_to_init - Reparent the calling kernel thread to the init task.
  *
  * If a kernel thread is launched as a result of a system call, or if
  * it ever exits, it should generally reparent itself to init so that
@@ -228,14 +234,13 @@ static inline int has_stopped_jobs(int pgrp)
  *
  * NOTE that reparent_to_init() gives the caller full capabilities.
  */
-void reparent_to_init(void)
+static void reparent_to_init(void)
 {
        write_lock_irq(&tasklist_lock);
 
        ptrace_unlink(current);
        /* Reparent to init */
        REMOVE_LINKS(current);
-       /* FIXME handle vchild_reaper/initpid */
        current->parent = child_reaper;
        current->real_parent = child_reaper;
        SET_LINKS(current);
@@ -243,7 +248,9 @@ void reparent_to_init(void)
        /* Set the exit signal to SIGCHLD so we signal init on exit */
        current->exit_signal = SIGCHLD;
 
-       if ((current->policy == SCHED_NORMAL) && (task_nice(current) < 0))
+       if ((current->policy == SCHED_NORMAL ||
+                       current->policy == SCHED_BATCH)
+                               && (task_nice(current) < 0))
                set_user_nice(current, 0);
        /* cpus_allowed? */
        /* rt_priority? */
@@ -258,7 +265,7 @@ void reparent_to_init(void)
 
 void __set_special_pids(pid_t session, pid_t pgrp)
 {
-       struct task_struct *curr = current;
+       struct task_struct *curr = current->group_leader;
 
        if (curr->signal->session != session) {
                detach_pid(curr, PIDTYPE_SID);
@@ -286,7 +293,7 @@ void set_special_pids(pid_t session, pid_t pgrp)
  */
 int allow_signal(int sig)
 {
-       if (sig < 1 || sig > _NSIG)
+       if (!valid_signal(sig) || sig < 1)
                return -EINVAL;
 
        spin_lock_irq(&current->sighand->siglock);
@@ -307,7 +314,7 @@ EXPORT_SYMBOL(allow_signal);
 
 int disallow_signal(int sig)
 {
-       if (sig < 1 || sig > _NSIG)
+       if (!valid_signal(sig) || sig < 1)
                return -EINVAL;
 
        spin_lock_irq(&current->sighand->siglock);
@@ -357,6 +364,9 @@ void daemonize(const char *name, ...)
        fs = init_task.fs;
        current->fs = fs;
        atomic_inc(&fs->count);
+       exit_namespace(current);
+       current->namespace = init_task.namespace;
+       get_namespace(current->namespace);
        exit_files(current);
        current->files = init_task.files;
        atomic_inc(&current->files->count);
@@ -366,23 +376,31 @@ void daemonize(const char *name, ...)
 
 EXPORT_SYMBOL(daemonize);
 
-static inline void close_files(struct files_struct * files)
+static void close_files(struct files_struct * files)
 {
        int i, j;
+       struct fdtable *fdt;
 
        j = 0;
+
+       /*
+        * It is safe to dereference the fd table without RCU or
+        * ->file_lock because this is the last reference to the
+        * files structure.
+        */
+       fdt = files_fdtable(files);
        for (;;) {
                unsigned long set;
                i = j * __NFDBITS;
-               if (i >= files->max_fdset || i >= files->max_fds)
+               if (i >= fdt->max_fdset || i >= fdt->max_fds)
                        break;
-               set = files->open_fds->fds_bits[j++];
+               set = fdt->open_fds->fds_bits[j++];
                while (set) {
                        if (set & 1) {
-                               struct file * file = xchg(&files->fd[i], NULL);
-                               if (file) 
+                               struct file * file = xchg(&fdt->fd[i], NULL);
+                               if (file)
                                        filp_close(file, files);
-                               // vx_openfd_dec(i);
+                               vx_openfd_dec(i);
                        }
                        i++;
                        set >>= 1;
@@ -405,18 +423,22 @@ struct files_struct *get_files_struct(struct task_struct *task)
 
 void fastcall put_files_struct(struct files_struct *files)
 {
+       struct fdtable *fdt;
+
        if (atomic_dec_and_test(&files->count)) {
                close_files(files);
                /*
                 * Free the fd and fdset arrays if we expanded them.
+                * If the fdtable was embedded, pass files for freeing
+                * at the end of the RCU grace period. Otherwise,
+                * you can free files immediately.
                 */
-               if (files->fd != &files->fd_array[0])
-                       free_fd_array(files->fd, files->max_fds);
-               if (files->max_fdset > __FD_SETSIZE) {
-                       free_fdset(files->open_fds, files->max_fdset);
-                       free_fdset(files->close_on_exec, files->max_fdset);
-               }
-               kmem_cache_free(files_cachep, files);
+               fdt = files_fdtable(files);
+               if (fdt == &files->fdtab)
+                       fdt->free_files = files;
+               else
+                       kmem_cache_free(files_cachep, files);
+               free_fdtable(fdt);
        }
 }
 
@@ -483,7 +505,7 @@ EXPORT_SYMBOL_GPL(exit_fs);
  * Turn us into a lazy TLB process if we
  * aren't already..
  */
-static inline void __exit_mm(struct task_struct * tsk)
+static void exit_mm(struct task_struct * tsk)
 {
        struct mm_struct *mm = tsk->mm;
 
@@ -514,30 +536,27 @@ static inline void __exit_mm(struct task_struct * tsk)
        task_lock(tsk);
        tsk->mm = NULL;
        up_read(&mm->mmap_sem);
-       ckrm_task_clear_mm(tsk, mm);
        enter_lazy_tlb(mm, current);
        task_unlock(tsk);
        mmput(mm);
 }
 
-void exit_mm(struct task_struct *tsk)
+static inline void choose_new_parent(task_t *p, task_t *reaper)
 {
-       __exit_mm(tsk);
-}
+       /* check for reaper context */
+       vxwprintk((p->xid != reaper->xid) && (reaper != child_reaper),
+               "rogue reaper: %p[%d,#%u] <> %p[%d,#%u]",
+               p, p->pid, p->xid, reaper, reaper->pid, reaper->xid);
 
-static inline void choose_new_parent(task_t *p, task_t *reaper, task_t *child_reaper)
-{
        /*
         * Make sure we're not reparenting to ourselves and that
         * the parent is not a zombie.
         */
-       BUG_ON(p == reaper || reaper->state >= EXIT_ZOMBIE || reaper->exit_state >= EXIT_ZOMBIE);
+       BUG_ON(p == reaper || reaper->exit_state >= EXIT_ZOMBIE);
        p->real_parent = reaper;
-       if (p->parent == p->real_parent)
-               BUG();
 }
 
-static inline void reparent_thread(task_t *p, task_t *father, int traced)
+static void reparent_thread(task_t *p, task_t *father, int traced)
 {
        /* We don't want people slaying init.  */
        if (p->exit_signal != -1)
@@ -545,7 +564,7 @@ static inline void reparent_thread(task_t *p, task_t *father, int traced)
 
        if (p->pdeath_signal)
                /* We already hold the tasklist_lock here.  */
-               group_send_sig_info(p->pdeath_signal, (void *) 0, p);
+               group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
 
        /* Move the child from its dying parent to the new one.  */
        if (unlikely(traced)) {
@@ -589,8 +608,8 @@ static inline void reparent_thread(task_t *p, task_t *father, int traced)
                int pgrp = process_group(p);
 
                if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
-                       __kill_pg_info(SIGHUP, (void *)1, pgrp);
-                       __kill_pg_info(SIGCONT, (void *)1, pgrp);
+                       __kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp);
+                       __kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp);
                }
        }
 }
@@ -601,20 +620,19 @@ static inline void reparent_thread(task_t *p, task_t *father, int traced)
  * group, and if no such member exists, give it to
  * the global child reaper process (ie "init")
  */
-static inline void forget_original_parent(struct task_struct * father,
+static void forget_original_parent(struct task_struct * father,
                                          struct list_head *to_release)
 {
        struct task_struct *p, *reaper = father;
        struct list_head *_p, *_n;
 
-       /* FIXME handle vchild_reaper/initpid */
        do {
                reaper = next_thread(reaper);
                if (reaper == father) {
-                       reaper = child_reaper;
+                       reaper = vx_child_reaper(father);
                        break;
                }
-       } while (reaper->exit_state >= EXIT_ZOMBIE);
+       } while (reaper->exit_state);
 
        /*
         * There are only two places where our children can be:
@@ -635,7 +653,7 @@ static inline void forget_original_parent(struct task_struct * father,
 
                if (father == p->real_parent) {
                        /* reparent with a reaper, real father it's us */
-                       choose_new_parent(p, reaper, child_reaper);
+                       choose_new_parent(p, vx_child_reaper(p));
                        reparent_thread(p, father, 0);
                } else {
                        /* reparent ptraced task to its real parent */
@@ -656,7 +674,8 @@ static inline void forget_original_parent(struct task_struct * father,
        }
        list_for_each_safe(_p, _n, &father->ptrace_children) {
                p = list_entry(_p,struct task_struct,ptrace_list);
-               choose_new_parent(p, reaper, child_reaper);
+
+               choose_new_parent(p, reaper);
                reparent_thread(p, father, 1);
        }
 }
@@ -671,9 +690,7 @@ static void exit_notify(struct task_struct *tsk)
        struct task_struct *t;
        struct list_head ptrace_dead, *_p, *_n;
 
-       ckrm_cb_exit(tsk);
-
-       if (signal_pending(tsk) && !tsk->signal->group_exit
+       if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
            && !thread_group_empty(tsk)) {
                /*
                 * This occurs when there was a race between our exit
@@ -728,8 +745,8 @@ static void exit_notify(struct task_struct *tsk)
            (t->signal->session == tsk->signal->session) &&
            will_become_orphaned_pgrp(process_group(tsk), tsk) &&
            has_stopped_jobs(process_group(tsk))) {
-               __kill_pg_info(SIGHUP, (void *)1, process_group(tsk));
-               __kill_pg_info(SIGCONT, (void *)1, process_group(tsk));
+               __kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk));
+               __kill_pg_info(SIGCONT, SEND_SIG_PRIV, process_group(tsk));
        }
 
        /* Let father know we died 
@@ -767,17 +784,12 @@ static void exit_notify(struct task_struct *tsk)
        }
 
        state = EXIT_ZOMBIE;
-       if (tsk->exit_signal == -1 && tsk->ptrace == 0)
+       if (tsk->exit_signal == -1 &&
+           (likely(tsk->ptrace == 0) ||
+            unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT)))
                state = EXIT_DEAD;
        tsk->exit_state = state;
 
-       /*
-        * Clear these here so that update_process_times() won't try to deliver
-        * itimer, profile or rlimit signals to this task while it is in late exit.
-        */
-       tsk->it_virt_value = 0;
-       tsk->it_prof_value = 0;
-
        write_unlock_irq(&tasklist_lock);
 
        list_for_each_safe(_p, _n, &ptrace_dead) {
@@ -789,10 +801,6 @@ static void exit_notify(struct task_struct *tsk)
        /* If the process is dead, release it - nobody will wait for it */
        if (state == EXIT_DEAD)
                release_task(tsk);
-
-       /* PF_DEAD causes final put_task_struct after we schedule. */
-       preempt_disable();
-       tsk->flags |= PF_DEAD;
 }
 
 fastcall NORET_TYPE void do_exit(long code)
@@ -802,6 +810,8 @@ fastcall NORET_TYPE void do_exit(long code)
 
        profile_task_exit(tsk);
 
+       WARN_ON(atomic_read(&tsk->fs_excl));
+
        if (unlikely(in_interrupt()))
                panic("Aiee, killing interrupt handler!");
        if (unlikely(!tsk->pid))
@@ -810,59 +820,89 @@ fastcall NORET_TYPE void do_exit(long code)
                panic("Attempted to kill init!");
        if (tsk->io_context)
                exit_io_context();
+
+       if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
+               current->ptrace_message = code;
+               ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
+       }
+
+       /*
+        * We're taking recursive faults here in do_exit. Safest is to just
+        * leave this task alone and wait for reboot.
+        */
+       if (unlikely(tsk->flags & PF_EXITING)) {
+               printk(KERN_ALERT
+                       "Fixing recursive fault but reboot is needed!\n");
+               set_current_state(TASK_UNINTERRUPTIBLE);
+               schedule();
+       }
+
        tsk->flags |= PF_EXITING;
-       del_timer_sync(&tsk->real_timer);
 
        if (unlikely(in_atomic()))
                printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
                                current->comm, current->pid,
                                preempt_count());
 
-       if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
-               current->ptrace_message = code;
-               ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
+       acct_update_integrals(tsk);
+       if (tsk->mm) {
+               update_hiwater_rss(tsk->mm);
+               update_hiwater_vm(tsk->mm);
        }
-
        group_dead = atomic_dec_and_test(&tsk->signal->live);
-       if (group_dead)
+       if (group_dead) {
+               hrtimer_cancel(&tsk->signal->real_timer);
+               exit_itimers(tsk->signal);
                acct_process(code);
-       if (current->tux_info) {
-#ifdef CONFIG_TUX_DEBUG
-               printk("Possibly unexpected TUX-thread exit(%ld) at %p?\n",
-                       code, __builtin_return_address(0));
-#endif
-               current->tux_exit();
        }
-       __exit_mm(tsk);
+       exit_mm(tsk);
 
        exit_sem(tsk);
        __exit_files(tsk);
        __exit_fs(tsk);
        exit_namespace(tsk);
        exit_thread();
+       cpuset_exit(tsk);
        exit_keys(tsk);
 
        if (group_dead && tsk->signal->leader)
                disassociate_ctty(1);
 
-       module_put(tsk->thread_info->exec_domain->module);
+       module_put(task_thread_info(tsk)->exec_domain->module);
        if (tsk->binfmt)
                module_put(tsk->binfmt->module);
 
        tsk->exit_code = code;
+       proc_exit_connector(tsk);
+       /* needs to stay before exit_notify() */
+       exit_vx_info_early(tsk, code);
        exit_notify(tsk);
 #ifdef CONFIG_NUMA
        mpol_free(tsk->mempolicy);
        tsk->mempolicy = NULL;
 #endif
+       /*
+        * If DEBUG_MUTEXES is on, make sure we are holding no locks:
+        */
+       mutex_debug_check_no_locks_held(tsk);
+
+       /* needs to stay after exit_notify() */
+       exit_vx_info(tsk, code);
+       exit_nx_info(tsk);
+
+       /* PF_DEAD causes final put_task_struct after we schedule. */
+       preempt_disable();
+       BUG_ON(tsk->flags & PF_DEAD);
+       tsk->flags |= PF_DEAD;
 
-       BUG_ON(!(current->flags & PF_DEAD));
        schedule();
        BUG();
        /* Avoid "noreturn function does return".  */
        for (;;) ;
 }
 
+EXPORT_SYMBOL_GPL(do_exit);
+
 NORET_TYPE void complete_and_exit(struct completion *comp, long code)
 {
        if (comp)
@@ -880,13 +920,6 @@ asmlinkage long sys_exit(int error_code)
 
 task_t fastcall *next_thread(const task_t *p)
 {
-#ifdef CONFIG_SMP
-       if (!p->sighand)
-               BUG();
-       if (!spin_is_locked(&p->sighand->siglock) &&
-                               !rwlock_is_locked(&tasklist_lock))
-               BUG();
-#endif
        return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
 }
 
@@ -901,18 +934,17 @@ do_group_exit(int exit_code)
 {
        BUG_ON(exit_code & 0x80); /* core dumps don't get here */
 
-       if (current->signal->group_exit)
+       if (current->signal->flags & SIGNAL_GROUP_EXIT)
                exit_code = current->signal->group_exit_code;
        else if (!thread_group_empty(current)) {
                struct signal_struct *const sig = current->signal;
                struct sighand_struct *const sighand = current->sighand;
                read_lock(&tasklist_lock);
                spin_lock_irq(&sighand->siglock);
-               if (sig->group_exit)
+               if (sig->flags & SIGNAL_GROUP_EXIT)
                        /* Another thread got here before we took the lock.  */
                        exit_code = sig->group_exit_code;
                else {
-                       sig->group_exit = 1;
                        sig->group_exit_code = exit_code;
                        zap_other_threads(current);
                }
@@ -1054,6 +1086,9 @@ static int wait_task_zombie(task_t *p, int noreap,
        }
 
        if (likely(p->real_parent == p->parent) && likely(p->signal)) {
+               struct signal_struct *psig;
+               struct signal_struct *sig;
+
                /*
                 * The resource counters for the group leader are in its
                 * own task_struct.  Those for dead threads in the group
@@ -1070,18 +1105,26 @@ static int wait_task_zombie(task_t *p, int noreap,
                 * here reaping other children at the same time.
                 */
                spin_lock_irq(&p->parent->sighand->siglock);
-               p->parent->signal->cutime +=
-                       p->utime + p->signal->utime + p->signal->cutime;
-               p->parent->signal->cstime +=
-                       p->stime + p->signal->stime + p->signal->cstime;
-               p->parent->signal->cmin_flt +=
-                       p->min_flt + p->signal->min_flt + p->signal->cmin_flt;
-               p->parent->signal->cmaj_flt +=
-                       p->maj_flt + p->signal->maj_flt + p->signal->cmaj_flt;
-               p->parent->signal->cnvcsw +=
-                       p->nvcsw + p->signal->nvcsw + p->signal->cnvcsw;
-               p->parent->signal->cnivcsw +=
-                       p->nivcsw + p->signal->nivcsw + p->signal->cnivcsw;
+               psig = p->parent->signal;
+               sig = p->signal;
+               psig->cutime =
+                       cputime_add(psig->cutime,
+                       cputime_add(p->utime,
+                       cputime_add(sig->utime,
+                                   sig->cutime)));
+               psig->cstime =
+                       cputime_add(psig->cstime,
+                       cputime_add(p->stime,
+                       cputime_add(sig->stime,
+                                   sig->cstime)));
+               psig->cmin_flt +=
+                       p->min_flt + sig->min_flt + sig->cmin_flt;
+               psig->cmaj_flt +=
+                       p->maj_flt + sig->maj_flt + sig->cmaj_flt;
+               psig->cnvcsw +=
+                       p->nvcsw + sig->nvcsw + sig->cnvcsw;
+               psig->cnivcsw +=
+                       p->nivcsw + sig->nivcsw + sig->cnivcsw;
                spin_unlock_irq(&p->parent->sighand->siglock);
        }
 
@@ -1092,7 +1135,7 @@ static int wait_task_zombie(task_t *p, int noreap,
        read_unlock(&tasklist_lock);
 
        retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
-       status = p->signal->group_exit
+       status = (p->signal->flags & SIGNAL_GROUP_EXIT)
                ? p->signal->group_exit_code : p->exit_code;
        if (!retval && stat_addr)
                retval = put_user(status, stat_addr);
@@ -1189,7 +1232,7 @@ static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap,
 
                exit_code = p->exit_code;
                if (unlikely(!exit_code) ||
-                   unlikely(p->state > TASK_STOPPED))
+                   unlikely(p->state & TASK_TRACED))
                        goto bail_ref;
                return wait_noreap_copyout(p, pid, uid,
                                           why, (exit_code << 8) | 0x7f,
@@ -1204,7 +1247,7 @@ static int wait_task_stopped(task_t *p, int delayed_group_leader, int noreap,
         * race with the EXIT_ZOMBIE case.
         */
        exit_code = xchg(&p->exit_code, 0);
-       if (unlikely(p->exit_state >= EXIT_ZOMBIE)) {
+       if (unlikely(p->exit_state)) {
                /*
                 * The task resumed and then died.  Let the next iteration
                 * catch it in EXIT_ZOMBIE.  Note that exit_code might
@@ -1282,16 +1325,17 @@ static int wait_task_continued(task_t *p, int noreap,
        if (unlikely(!p->signal))
                return 0;
 
-       if (p->signal->stop_state >= 0)
+       if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
                return 0;
 
        spin_lock_irq(&p->sighand->siglock);
-       if (p->signal->stop_state >= 0) { /* Re-check with the lock held.  */
+       /* Re-check with the lock held.  */
+       if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
                spin_unlock_irq(&p->sighand->siglock);
                return 0;
        }
        if (!noreap)
-               p->signal->stop_state = 0;
+               p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
        spin_unlock_irq(&p->sighand->siglock);
 
        pid = p->pid;
@@ -1340,7 +1384,7 @@ static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
        struct task_struct *tsk;
        int flag, retval;
 
-       add_wait_queue(&current->wait_chldexit,&wait);
+       add_wait_queue(&current->signal->wait_chldexit,&wait);
 repeat:
        /*
         * We will set this flag if we see any child that might later
@@ -1364,6 +1408,15 @@ repeat:
 
                        switch (p->state) {
                        case TASK_TRACED:
+                               /*
+                                * When we hit the race with PTRACE_ATTACH,
+                                * we will not report this child.  But the
+                                * race means it has not yet been moved to
+                                * our ptrace_children list, so we need to
+                                * set the flag here to avoid a spurious ECHILD
+                                * when the race happens with the only child.
+                                */
+                               flag = 1;
                                if (!my_ptrace_child(p))
                                        continue;
                                /*FALLTHROUGH*/
@@ -1415,7 +1468,6 @@ check_continued:
                                flag = 1;
                                if (!unlikely(options & WCONTINUED))
                                        continue;
-
                                retval = wait_task_continued(
                                        p, (options & WNOWAIT),
                                        infop, stat_addr, ru);
@@ -1455,7 +1507,7 @@ check_continued:
        retval = -ECHILD;
 end:
        current->state = TASK_RUNNING;
-       remove_wait_queue(&current->wait_chldexit,&wait);
+       remove_wait_queue(&current->signal->wait_chldexit,&wait);
        if (infop) {
                if (retval > 0)
                retval = 0;