1 files changed, 37 insertions, 14 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 9064bf9e131b..56e4e07e45f7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -193,7 +193,10 @@ static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 
         down_write(&oldmm->mmap_sem);
         flush_cache_mm(oldmm);
-        down_write(&mm->mmap_sem);
+        /*
+         * Not linked in yet - no deadlock potential:
+         */
+        down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
 
         mm->locked_vm = 0;
         mm->mmap = NULL;
@@ -919,10 +922,6 @@ static inline void rt_mutex_init_task(struct task_struct *p)
         spin_lock_init(&p->pi_lock);
         plist_head_init(&p->pi_waiters, &p->pi_lock);
         p->pi_blocked_on = NULL;
-# ifdef CONFIG_DEBUG_RT_MUTEXES
-        spin_lock_init(&p->held_list_lock);
-        INIT_LIST_HEAD(&p->held_list_head);
-# endif
 #endif
 }
 
@@ -934,13 +933,13 @@ static inline void rt_mutex_init_task(struct task_struct *p)
  * parts of the process environment (as per the clone
  * flags). The actual kick-off is left to the caller.
  */
-static task_t *copy_process(unsigned long clone_flags,
-                                 unsigned long stack_start,
-                                 struct pt_regs *regs,
-                                 unsigned long stack_size,
-                                 int __user *parent_tidptr,
-                                 int __user *child_tidptr,
-                                 int pid)
+static struct task_struct *copy_process(unsigned long clone_flags,
+                                        unsigned long stack_start,
+                                        struct pt_regs *regs,
+                                        unsigned long stack_size,
+                                        int __user *parent_tidptr,
+                                        int __user *child_tidptr,
+                                        int pid)
 {
         int retval;
         struct task_struct *p = NULL;
@@ -972,6 +971,10 @@ static task_t *copy_process(unsigned long clone_flags,
         if (!p)
                 goto fork_out;
 
+#ifdef CONFIG_TRACE_IRQFLAGS
+        DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
+        DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
+#endif
         retval = -EAGAIN;
         if (atomic_read(&p->user->processes) >=
                         p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
@@ -1046,6 +1049,26 @@ static task_t *copy_process(unsigned long clone_flags,
         }
         mpol_fix_fork_child_flag(p);
 #endif
+#ifdef CONFIG_TRACE_IRQFLAGS
+        p->irq_events = 0;
+        p->hardirqs_enabled = 0;
+        p->hardirq_enable_ip = 0;
+        p->hardirq_enable_event = 0;
+        p->hardirq_disable_ip = _THIS_IP_;
+        p->hardirq_disable_event = 0;
+        p->softirqs_enabled = 1;
+        p->softirq_enable_ip = _THIS_IP_;
+        p->softirq_enable_event = 0;
+        p->softirq_disable_ip = 0;
+        p->softirq_disable_event = 0;
+        p->hardirq_context = 0;
+        p->softirq_context = 0;
+#endif
+#ifdef CONFIG_LOCKDEP
+        p->lockdep_depth = 0; /* no locks held yet */
+        p->curr_chain_key = 0;
+        p->lockdep_recursion = 0;
+#endif
 
         rt_mutex_init_task(p);
 
@@ -1271,9 +1294,9 @@ struct pt_regs * __devinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
         return regs;
 }
 
-task_t * __devinit fork_idle(int cpu)
+struct task_struct * __devinit fork_idle(int cpu)
 {
-        task_t *task;
+        struct task_struct *task;
         struct pt_regs regs;
 
         task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL, NULL, 0);