[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>
diff --git a/kernel/exit.c b/kernel/exit.c
index d891883..4b6fb05 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -487,6 +487,18 @@
EXPORT_SYMBOL(put_files_struct);
+void reset_files_struct(struct task_struct *tsk, struct files_struct *files)
+{
+ struct files_struct *old;
+
+ old = tsk->files;
+ task_lock(tsk);
+ tsk->files = files;
+ task_unlock(tsk);
+ put_files_struct(old);
+}
+EXPORT_SYMBOL(reset_files_struct);
+
static inline void __exit_files(struct task_struct *tsk)
{
struct files_struct * files = tsk->files;