[PATCH] Fix unserialized task->files changing

Fixed race on put_files_struct on exec with proc.  Restoring files on
current on error path may lead to proc having a pointer to already kfree-d
files_struct.

->files changing at exit.c and khtread.c are safe as exit_files() makes all
things under lock.

Found during OpenVZ stress testing.

[akpm@osdl.org: add export]
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 66ba137f8661..1713c48fef54 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -215,10 +215,8 @@ _error:
         bprm->interp_flags = 0;
         bprm->interp_data = 0;
 _unshare:
-        if (files) {
-                put_files_struct(current->files);
-                current->files = files;
-        }
+        if (files)
+                reset_files_struct(current, files);
         goto _ret;
 }