[PATCH] files: fix preemption issues

With the new fdtable locking rules, you have to protect fdtable with either
->file_lock or rcu_read_lock/unlock().  There are some places where we
aren't doing either.  This patch fixes those places.

Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 6d2089a1bce7..ee6d8b8abef5 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -371,6 +371,12 @@ static inline void close_files(struct files_struct * files)
         struct fdtable *fdt;
 
         j = 0;
+
+        /*
+         * It is safe to dereference the fd table without RCU or
+         * ->file_lock because this is the last reference to the
+         * files structure.
+         */
         fdt = files_fdtable(files);
         for (;;) {
                 unsigned long set;