Revert "[PATCH] fix Data Acess error in dup_fd"

This reverts commit 0130b0b3

.

Sergey Vlasov points out (and Vadim Lobanov concurs) that the bug it was
supposed to fix must be some unrelated memory corruption, and the "fix"
actually causes more problems:

  "However, the new code does not look safe in all cases.  If some other
   task has opened more files while dup_fd() released oldf->file_lock, the
   new code will update open_files to the new larger value.  But newf was
   allocated with the old smaller value of open_files, therefore subsequent
   accesses to newf may try to write into unallocated memory."

so revert it.

Cc: Sharyathi Nagesh <sharyath@in.ibm.com>
Cc: Sergey Vlasov <vsu@altlinux.ru>
Cc: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/fork.c

@@ -687,7 +687,6 @@ static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
 		 * the latest pointer.
 		 */
 		spin_lock(&oldf->file_lock);
-		open_files = count_open_files(old_fdt);
 		old_fdt = files_fdtable(oldf);
 	}