On 01/08, Michel Lespinasse wrote: > > Like others before me, I have discovered how easy it is to DOS a > system by abusing the rwlock_t unfairness and causing the > tasklist_lock read side to be continuously held
Yes. Plus it has perfomance problems. It should die. We still need the global lock to protect, say, init_task.tasks list, but otherwise we need the per-process locking. > - Would there be any fundamental objection to implementing a fair > rwlock_t and dealing with the reentrancy issues in tasklist_lock ? My > proposal there would be along the lines of: I don't really understand your proposal in details, but until we kill tasklist_lock, perhaps it makes sense to implement something simple, say, write-biased rwlock and add "int task_struct->tasklist_read_lock_counter" to avoid the read-write-read deadlock. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
