Messages in this thread | | | Date | Mon, 9 Oct 2017 16:17:37 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v4 1/2] pid: Replace pid bitmap implementation with IDR API |
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On Mon, 9 Oct 2017 17:13:43 -0400 Gargi Sharma <gs051095@gmail.com> wrote:
> This patch replaces the current bitmap implemetation for > Process ID allocation. Functions that are no longer required, > for example, free_pidmap(), alloc_pidmap(), etc. are removed. > The rest of the functions are modified to use the IDR API. > The change was made to make the PID allocation less complex by > replacing custom code with calls to generic API. >
I can't say I really understand the locking here.
> > ... > > @@ -240,17 +230,11 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) > * > */ > read_lock(&tasklist_lock); > - nr = next_pidmap(pid_ns, 1); > - while (nr > 0) { > - rcu_read_lock(); > - > - task = pid_task(find_vpid(nr), PIDTYPE_PID); > + nr = 2; > + idr_for_each_entry_continue(&pid_ns->idr, pid, nr) { > + task = pid_task(pid, PIDTYPE_PID); > if (task && !__fatal_signal_pending(task)) > send_sig_info(SIGKILL, SEND_SIG_FORCED, task); > - > - rcu_read_unlock(); > - > - nr = next_pidmap(pid_ns, nr); > } > read_unlock(&tasklist_lock);
Especially here. I don't think pidmap_lock is held. Is that IDR iteration safe?
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