1 files changed, 19 insertions, 13 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 0a3757067631..71e1a523e209 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1323,12 +1323,9 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
                 err = -ESRCH;
                 goto out;
         }
-        mm = get_task_mm(task);
-        rcu_read_unlock();
+        get_task_struct(task);
 
         err = -EINVAL;
-        if (!mm)
-                goto out;
 
         /*
          * Check if this process has the right to modify the specified
@@ -1336,14 +1333,13 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
          * capabilities, superuser privileges or the same
          * userid as the target process.
          */
-        rcu_read_lock();
         tcred = __task_cred(task);
         if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
             cred->uid  != tcred->suid && cred->uid  != tcred->uid &&
             !capable(CAP_SYS_NICE)) {
                 rcu_read_unlock();
                 err = -EPERM;
-                goto out;
+                goto out_put;
         }
         rcu_read_unlock();
 
@@ -1351,26 +1347,36 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
         /* Is the user allowed to access the target nodes? */
         if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
                 err = -EPERM;
-                goto out;
+                goto out_put;
         }
 
         if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
                 err = -EINVAL;
-                goto out;
+                goto out_put;
         }
 
         err = security_task_movememory(task);
         if (err)
-                goto out;
+                goto out_put;
 
-        err = do_migrate_pages(mm, old, new,
-                capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
-out:
+        mm = get_task_mm(task);
+        put_task_struct(task);
         if (mm)
-                mmput(mm);
+                err = do_migrate_pages(mm, old, new,
+                        capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
+        else
+                err = -EINVAL;
+
+        mmput(mm);
+out:
         NODEMASK_SCRATCH_FREE(scratch);
 
         return err;
+
+out_put:
+        put_task_struct(task);
+        goto out;
+
 }