1 files changed, 55 insertions, 83 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 5b2959b3ffc2..b6cce14ba047 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -87,6 +87,14 @@ DEFINE_PER_CPU(unsigned long, process_counts) = 0;
 
 __cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */
 
+#ifdef CONFIG_PROVE_RCU
+int lockdep_tasklist_lock_is_held(void)
+{
+        return lockdep_is_held(&tasklist_lock);
+}
+EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
+#endif /* #ifdef CONFIG_PROVE_RCU */
+
 int nr_processes(void)
 {
         int cpu;
@@ -157,6 +165,18 @@ void free_task(struct task_struct *tsk)
 }
 EXPORT_SYMBOL(free_task);
 
+static inline void free_signal_struct(struct signal_struct *sig)
+{
+        taskstats_tgid_free(sig);
+        kmem_cache_free(signal_cachep, sig);
+}
+
+static inline void put_signal_struct(struct signal_struct *sig)
+{
+        if (atomic_dec_and_test(&sig->sigcnt))
+                free_signal_struct(sig);
+}
+
 void __put_task_struct(struct task_struct *tsk)
 {
         WARN_ON(!tsk->exit_state);
@@ -165,6 +185,7 @@ void __put_task_struct(struct task_struct *tsk)
 
         exit_creds(tsk);
         delayacct_tsk_free(tsk);
+        put_signal_struct(tsk->signal);
 
         if (!profile_handoff_task(tsk))
                 free_task(tsk);
@@ -328,15 +349,17 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
                 if (!tmp)
                         goto fail_nomem;
                 *tmp = *mpnt;
+                INIT_LIST_HEAD(&tmp->anon_vma_chain);
                 pol = mpol_dup(vma_policy(mpnt));
                 retval = PTR_ERR(pol);
                 if (IS_ERR(pol))
                         goto fail_nomem_policy;
                 vma_set_policy(tmp, pol);
+                if (anon_vma_fork(tmp, mpnt))
+                        goto fail_nomem_anon_vma_fork;
                 tmp->vm_flags &= ~VM_LOCKED;
                 tmp->vm_mm = mm;
                 tmp->vm_next = NULL;
-                anon_vma_link(tmp);
                 file = tmp->vm_file;
                 if (file) {
                         struct inode *inode = file->f_path.dentry->d_inode;
@@ -391,6 +414,8 @@ out:
         flush_tlb_mm(oldmm);
         up_write(&oldmm->mmap_sem);
         return retval;
+fail_nomem_anon_vma_fork:
+        mpol_put(pol);
 fail_nomem_policy:
         kmem_cache_free(vm_area_cachep, tmp);
 fail_nomem:
@@ -454,8 +479,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
                 (current->mm->flags & MMF_INIT_MASK) : default_dump_filter;
         mm->core_state = NULL;
         mm->nr_ptes = 0;
-        set_mm_counter(mm, file_rss, 0);
-        set_mm_counter(mm, anon_rss, 0);
+        memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
         spin_lock_init(&mm->page_table_lock);
         mm->free_area_cache = TASK_UNMAPPED_BASE;
         mm->cached_hole_size = ~0UL;
@@ -824,23 +848,14 @@ void __cleanup_sighand(struct sighand_struct *sighand)
  */
 static void posix_cpu_timers_init_group(struct signal_struct *sig)
 {
+        unsigned long cpu_limit;
+
         /* Thread group counters. */
         thread_group_cputime_init(sig);
 
-        /* Expiration times and increments. */
-        sig->it[CPUCLOCK_PROF].expires = cputime_zero;
-        sig->it[CPUCLOCK_PROF].incr = cputime_zero;
-        sig->it[CPUCLOCK_VIRT].expires = cputime_zero;
-        sig->it[CPUCLOCK_VIRT].incr = cputime_zero;
-
-        /* Cached expiration times. */
-        sig->cputime_expires.prof_exp = cputime_zero;
-        sig->cputime_expires.virt_exp = cputime_zero;
-        sig->cputime_expires.sched_exp = 0;
-
-        if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
-                sig->cputime_expires.prof_exp =
-                        secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
+        cpu_limit = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
+        if (cpu_limit != RLIM_INFINITY) {
+                sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit);
                 sig->cputimer.running = 1;
         }
 
@@ -857,54 +872,30 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
         if (clone_flags & CLONE_THREAD)
                 return 0;
 
-        sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
+        sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
         tsk->signal = sig;
         if (!sig)
                 return -ENOMEM;
 
-        atomic_set(&sig->count, 1);
+        sig->nr_threads = 1;
         atomic_set(&sig->live, 1);
+        atomic_set(&sig->sigcnt, 1);
         init_waitqueue_head(&sig->wait_chldexit);
-        sig->flags = 0;
         if (clone_flags & CLONE_NEWPID)
                 sig->flags |= SIGNAL_UNKILLABLE;
-        sig->group_exit_code = 0;
-        sig->group_exit_task = NULL;
-        sig->group_stop_count = 0;
         sig->curr_target = tsk;
         init_sigpending(&sig->shared_pending);
         INIT_LIST_HEAD(&sig->posix_timers);
 
         hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-        sig->it_real_incr.tv64 = 0;
         sig->real_timer.function = it_real_fn;
 
-        sig->leader = 0;        /* session leadership doesn't inherit */
-        sig->tty_old_pgrp = NULL;
-        sig->tty = NULL;
-
-        sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero;
-        sig->gtime = cputime_zero;
-        sig->cgtime = cputime_zero;
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
-        sig->prev_utime = sig->prev_stime = cputime_zero;
-#endif
-        sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0;
-        sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0;
-        sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0;
-        sig->maxrss = sig->cmaxrss = 0;
-        task_io_accounting_init(&sig->ioac);
-        sig->sum_sched_runtime = 0;
-        taskstats_tgid_init(sig);
-
         task_lock(current->group_leader);
         memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
         task_unlock(current->group_leader);
 
         posix_cpu_timers_init_group(sig);
 
-        acct_init_pacct(&sig->pacct);
-
         tty_audit_fork(sig);
 
         sig->oom_adj = current->signal->oom_adj;
@@ -912,13 +903,6 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
         return 0;
 }
 
-void __cleanup_signal(struct signal_struct *sig)
-{
-        thread_group_cputime_free(sig);
-        tty_kref_put(sig->tty);
-        kmem_cache_free(signal_cachep, sig);
-}
-
 static void copy_flags(unsigned long clone_flags, struct task_struct *p)
 {
         unsigned long new_flags = p->flags;
@@ -1033,7 +1017,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 #endif
         retval = -EAGAIN;
         if (atomic_read(&p->real_cred->user->processes) >=
-                        p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
+                        task_rlimit(p, RLIMIT_NPROC)) {
                 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
                     p->real_cred->user != INIT_USER)
                         goto bad_fork_free;
@@ -1075,6 +1059,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         p->prev_utime = cputime_zero;
         p->prev_stime = cputime_zero;
 #endif
+#if defined(SPLIT_RSS_COUNTING)
+        memset(&p->rss_stat, 0, sizeof(p->rss_stat));
+#endif
 
         p->default_timer_slack_ns = current->timer_slack_ns;
 
@@ -1132,10 +1119,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         p->memcg_batch.memcg = NULL;
 #endif
 
-        p->bts = NULL;
-
-        p->stack_start = stack_start;
-
         /* Perform scheduler related setup. Assign this task to a CPU. */
         sched_fork(p, clone_flags);
 
@@ -1241,21 +1224,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         /* Need tasklist lock for parent etc handling! */
         write_lock_irq(&tasklist_lock);
 
-        /*
-         * The task hasn't been attached yet, so its cpus_allowed mask will
-         * not be changed, nor will its assigned CPU.
-         *
-         * The cpus_allowed mask of the parent may have changed after it was
-         * copied first time - so re-copy it here, then check the child's CPU
-         * to ensure it is on a valid CPU (and if not, just force it back to
-         * parent's CPU). This avoids alot of nasty races.
-         */
-        p->cpus_allowed = current->cpus_allowed;
-        p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed;
-        if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
-                        !cpu_online(task_cpu(p))))
-                set_task_cpu(p, smp_processor_id());
-
         /* CLONE_PARENT re-uses the old parent */
         if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
                 p->real_parent = current->real_parent;
@@ -1284,8 +1252,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         }
 
         if (clone_flags & CLONE_THREAD) {
-                atomic_inc(&current->signal->count);
+                current->signal->nr_threads++;
                 atomic_inc(&current->signal->live);
+                atomic_inc(&current->signal->sigcnt);
                 p->group_leader = current->group_leader;
                 list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
         }
@@ -1298,7 +1267,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
                                 p->nsproxy->pid_ns->child_reaper = p;
 
                         p->signal->leader_pid = pid;
-                        tty_kref_put(p->signal->tty);
                         p->signal->tty = tty_kref_get(current->signal->tty);
                         attach_pid(p, PIDTYPE_PGID, task_pgrp(current));
                         attach_pid(p, PIDTYPE_SID, task_session(current));
@@ -1331,7 +1299,7 @@ bad_fork_cleanup_mm:
                 mmput(p->mm);
 bad_fork_cleanup_signal:
         if (!(clone_flags & CLONE_THREAD))
-                __cleanup_signal(p->signal);
+                free_signal_struct(p->signal);
 bad_fork_cleanup_sighand:
         __cleanup_sighand(p->sighand);
 bad_fork_cleanup_fs:
@@ -1366,6 +1334,16 @@ noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_re
         return regs;
 }
 
+static inline void init_idle_pids(struct pid_link *links)
+{
+        enum pid_type type;
+
+        for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
+                INIT_HLIST_NODE(&links[type].node); /* not really needed */
+                links[type].pid = &init_struct_pid;
+        }
+}
+
 struct task_struct * __cpuinit fork_idle(int cpu)
 {
         struct task_struct *task;
@@ -1373,8 +1351,10 @@ struct task_struct * __cpuinit fork_idle(int cpu)
 
         task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL,
                             &init_struct_pid, 0);
-        if (!IS_ERR(task))
+        if (!IS_ERR(task)) {
+                init_idle_pids(task->pids);
                 init_idle(task, cpu);
+        }
 
         return task;
 }
@@ -1546,14 +1526,6 @@ static void check_unshare_flags(unsigned long *flags_ptr)
                 *flags_ptr |= CLONE_SIGHAND;
 
         /*
-         * If unsharing signal handlers and the task was created
-         * using CLONE_THREAD, then must unshare the thread
-         */
-        if ((*flags_ptr & CLONE_SIGHAND) &&
-            (atomic_read(&current->signal->count) > 1))
-                *flags_ptr |= CLONE_THREAD;
-
-        /*
          * If unsharing namespace, must also unshare filesystem information.
          */
         if (*flags_ptr & CLONE_NEWNS)