Andrew Morton <[EMAIL PROTECTED]> writes: > On Fri, 13 Apr 2007 17:02:01 +0400 > Oleg Nesterov <[EMAIL PROTECTED]> wrote: > >> If kernel_thread(kthread) succeeds, kthread() can not fail on its path to >> complete(&create->started) + schedule(). After that it can't be woken because >> nobody can see the new task yet. This means: >> >> - we don't need tasklist_lock for find_task_by_pid(). >> >> - create_kthread() doesn't need to wait for create->started. Instead, >> kthread_create() first waits for create->created to get the result of >> kernel_thread(), then waits for create->started to synchronize with >> kthread(). > > Why don't we need tasklist_lock for find_task_by_pid()? I'd have though that > we'd at least need rcu_read_lock(), and I'm not sure that the implicit > understanding of pid-management internals here is a great idea.
We need rcu_read_lock(). Or else something could permute the pid hash table and get us into trouble. Eric - 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/
