releases/3.2.6/proc-mem_release-should-check-mm-null.patch

   1 From 71879d3cb3dd8f2dfdefb252775c1b3ea04a3dd4 Mon Sep 17 00:00:00 2001
   2 From: Oleg Nesterov <oleg@redhat.com>
   3 Date: Tue, 31 Jan 2012 17:14:38 +0100
   4 Subject: proc: mem_release() should check mm != NULL
   5
   6 From: Oleg Nesterov <oleg@redhat.com>
   7
   8 commit 71879d3cb3dd8f2dfdefb252775c1b3ea04a3dd4 upstream.
   9
  10 mem_release() can hit mm == NULL, add the necessary check.
  11
  12 Signed-off-by: Oleg Nesterov <oleg@redhat.com>
  13 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  14 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  15
  16 ---
  17  fs/proc/base.c |    4 ++--
  18  1 file changed, 2 insertions(+), 2 deletions(-)
  19
  20 --- a/fs/proc/base.c
  21 +++ b/fs/proc/base.c
  22 @@ -886,8 +886,8 @@ loff_t mem_lseek(struct file *file, loff
  23  static int mem_release(struct inode *inode, struct file *file)
  24  {
  25         struct mm_struct *mm = file->private_data;
  26 -
  27 -       mmput(mm);
  28 +       if (mm)
  29 +               mmput(mm);
  30         return 0;
  31  }
  32