Re: closefd: closes a file of any process

> Obviously you must lock files_lock, but all necessary spinlocks exist:

At least in a 2.2.x there is no files_lock, it seems it's protected with
kernel_lock()'s spinlock

Anyway... in the following example, I think thre could be a problem
please tell me if I'm right or not

> 
>     read_lock(&tasklist_lock);
>     tsk = find_task_by_pid();
>     get_task_struct(tsk);
>     read_unlock(&tasklist_lock); --> here you unlock the task
>     task_lock(&tsk); --> here you lock again it (for resource de/allocation

      Is is posible that tsk doesn't longer exist when task_lock() is called?

>     files = tsk->files;
>     atomic_inc(&files->count);
>     task_unlock(&tsk);
>     free_task_struct(tsk);
>     __do_close(files, fd, release); /* do_close, but on files instead of
>                                                    * current->files */
>     put_files_struct(files);
> 

	Ulisses

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