1 files changed, 50 insertions, 22 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 4187b4e9cdb3..abf3208c3f60 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -75,9 +75,13 @@ int proc_exe_link(struct inode *inode, struct dentry **dentry, struct vfsmount *
 {
         struct vm_area_struct * vma;
         int result = -ENOENT;
-        struct task_struct *task = proc_task(inode);
-        struct mm_struct * mm = get_task_mm(task);
+        struct task_struct *task = get_proc_task(inode);
+        struct mm_struct * mm = NULL;
 
+        if (task) {
+                mm = get_task_mm(task);
+                put_task_struct(task);
+        }
         if (!mm)
                 goto out;
         down_read(&mm->mmap_sem);
@@ -120,7 +124,8 @@ struct mem_size_stats
 
 static int show_map_internal(struct seq_file *m, void *v, struct mem_size_stats *mss)
 {
-        struct task_struct *task = m->private;
+        struct proc_maps_private *priv = m->private;
+        struct task_struct *task = priv->task;
         struct vm_area_struct *vma = v;
         struct mm_struct *mm = vma->vm_mm;
         struct file *file = vma->vm_file;
@@ -295,12 +300,16 @@ static int show_smap(struct seq_file *m, void *v)
 
 static void *m_start(struct seq_file *m, loff_t *pos)
 {
-        struct task_struct *task = m->private;
+        struct proc_maps_private *priv = m->private;
         unsigned long last_addr = m->version;
         struct mm_struct *mm;
-        struct vm_area_struct *vma, *tail_vma;
+        struct vm_area_struct *vma, *tail_vma = NULL;
         loff_t l = *pos;
 
+        /* Clear the per syscall fields in priv */
+        priv->task = NULL;
+        priv->tail_vma = NULL;
+
         /*
          * We remember last_addr rather than next_addr to hit with
          * mmap_cache most of the time. We have zero last_addr at
@@ -311,11 +320,15 @@ static void *m_start(struct seq_file *m, loff_t *pos)
         if (last_addr == -1UL)
                 return NULL;
 
-        mm = get_task_mm(task);
+        priv->task = get_tref_task(priv->tref);
+        if (!priv->task)
+                return NULL;
+
+        mm = get_task_mm(priv->task);
         if (!mm)
                 return NULL;
 
-        tail_vma = get_gate_vma(task);
+        priv->tail_vma = tail_vma = get_gate_vma(priv->task);
         down_read(&mm->mmap_sem);
 
         /* Start with last addr hint */
@@ -350,11 +363,9 @@ out:
         return tail_vma;
 }
 
-static void m_stop(struct seq_file *m, void *v)
+static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma)
 {
-        struct task_struct *task = m->private;
-        struct vm_area_struct *vma = v;
-        if (vma && vma != get_gate_vma(task)) {
+        if (vma && vma != priv->tail_vma) {
                 struct mm_struct *mm = vma->vm_mm;
                 up_read(&mm->mmap_sem);
                 mmput(mm);
@@ -363,17 +374,27 @@ static void m_stop(struct seq_file *m, void *v)
 
 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
 {
-        struct task_struct *task = m->private;
+        struct proc_maps_private *priv = m->private;
         struct vm_area_struct *vma = v;
-        struct vm_area_struct *tail_vma = get_gate_vma(task);
+        struct vm_area_struct *tail_vma = priv->tail_vma;
 
         (*pos)++;
         if (vma && (vma != tail_vma) && vma->vm_next)
                 return vma->vm_next;
-        m_stop(m, v);
+        vma_stop(priv, vma);
         return (vma != tail_vma)? tail_vma: NULL;
 }
 
+static void m_stop(struct seq_file *m, void *v)
+{
+        struct proc_maps_private *priv = m->private;
+        struct vm_area_struct *vma = v;
+
+        vma_stop(priv, vma);
+        if (priv->task)
+                put_task_struct(priv->task);
+}
+
 static struct seq_operations proc_pid_maps_op = {
         .start  = m_start,
         .next   = m_next,
@@ -391,11 +412,18 @@ static struct seq_operations proc_pid_smaps_op = {
 static int do_maps_open(struct inode *inode, struct file *file,
                         struct seq_operations *ops)
 {
-        struct task_struct *task = proc_task(inode);
-        int ret = seq_open(file, ops);
-        if (!ret) {
-                struct seq_file *m = file->private_data;
-                m->private = task;
+        struct proc_maps_private *priv;
+        int ret = -ENOMEM;
+        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+        if (priv) {
+                priv->tref = proc_tref(inode);
+                ret = seq_open(file, ops);
+                if (!ret) {
+                        struct seq_file *m = file->private_data;
+                        m->private = priv;
+                } else {
+                        kfree(priv);
+                }
         }
         return ret;
 }
@@ -409,7 +437,7 @@ struct file_operations proc_maps_operations = {
         .open           = maps_open,
         .read           = seq_read,
         .llseek         = seq_lseek,
-        .release        = seq_release,
+        .release        = seq_release_private,
 };
 
 #ifdef CONFIG_NUMA
@@ -431,7 +459,7 @@ struct file_operations proc_numa_maps_operations = {
         .open           = numa_maps_open,
         .read           = seq_read,
         .llseek         = seq_lseek,
-        .release        = seq_release,
+        .release        = seq_release_private,
 };
 #endif
 
@@ -444,5 +472,5 @@ struct file_operations proc_smaps_operations = {
         .open           = smaps_open,
         .read           = seq_read,
         .llseek         = seq_lseek,
-        .release        = seq_release,
+        .release        = seq_release_private,
 };