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

This reverts commit 0130b0b32ee53dc7add773fcea984f6a26ef1da3.

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>

diff --git a/kernel/fork.c b/kernel/fork.c
index 4b4eab2a316136fc3bd44bdb7e55eeee509b1030..3da978eec791216dd796cd704aed67b263713fa1 100644 (file)
--- a/kernel/fork.c
+++ b/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);
        }