From: Andrew Morton <akpm@linux-foundation.org>
To: Gargi Sharma <gs051095@gmail.com>
Cc: linux-kernel@vger.kernel.org, riel@surriel.com,
julia.lawall@lip6.fr, mingo@kernel.org,
pasha.tatashin@oracle.com, ktkhai@virtuozzo.com, oleg@redhat.com,
ebiederm@xmission.com, hch@infradead.org
Subject: Re: [PATCH v4 1/2] pid: Replace pid bitmap implementation with IDR API
Date: Mon, 9 Oct 2017 16:17:37 -0700 [thread overview]
Message-ID: <20171009161737.ea8c62441cc12dfd909ee0b2@linux-foundation.org> (raw)
In-Reply-To: <1507583624-22146-2-git-send-email-gs051095@gmail.com>
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?
next prev parent reply other threads:[~2017-10-09 23:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-09 21:13 [PATCH v4 0/2] Replacing PID bitmap implementation with IDR API Gargi Sharma
2017-10-09 21:13 ` [PATCH v4 1/2] pid: Replace pid " Gargi Sharma
2017-10-09 23:17 ` Andrew Morton [this message]
2017-10-10 11:50 ` Oleg Nesterov
2017-10-10 12:35 ` Gargi Sharma
2017-10-10 14:15 ` Oleg Nesterov
2017-10-10 15:46 ` Rik van Riel
2017-10-10 16:11 ` Gargi Sharma
2017-10-10 17:51 ` Rik van Riel
2017-10-10 13:44 ` Rik van Riel
2017-10-09 21:13 ` [PATCH v4 2/2] pid: Remove pidhash Gargi Sharma
2017-10-11 9:47 ` kbuild test robot
2017-10-11 14:15 ` Rik van Riel
2017-10-11 14:15 ` Rik van Riel
2017-10-11 21:22 ` Luck, Tony
2017-10-11 21:22 ` Luck, Tony
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