proc: mem_release() should check mm != NULL

mem_release() can hit mm == NULL, add the necessary check. Cc: stable@kernel.org Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mariux64 · Feb 1, 2012 · 71879d3 · 71879d3
1 parent 879a5a0
commit 71879d3
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/fs/proc/base.c b/fs/proc/base.c
@@ -822,8 +822,8 @@ loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 static int mem_release(struct inode *inode, struct file *file)
 {
 	struct mm_struct *mm = file->private_data;
-
-	mmput(mm);
+	if (mm)
+		mmput(mm);
 	return 0;
 }