From: Oleg Nesterov <oleg@redhat.com>
To: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Christian Brauner <brauner@kernel.org>,
Shuah Khan <shuah@kernel.org>, Jan Kara <jack@suse.cz>,
Aleksa Sarai <cyphar@cyphar.com>,
Andrei Vagin <avagin@google.com>, Kirill Tkhai <tkhai@ya.ru>,
Alexander Mikhalitsyn <alexander@mihalicyn.com>,
Adrian Reber <areber@redhat.com>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH 1/2] pid_namespace: allow opening pid_for_children before init was created
Date: Sun, 22 Feb 2026 17:55:05 +0100 [thread overview]
Message-ID: <aZs06UgTFYg_ctlN@redhat.com> (raw)
In-Reply-To: <aZsi8Z4Y2qqpdZGH@redhat.com>
On 02/22, Oleg Nesterov wrote:
>
> Pavel,
>
> Your patch doesn't apply to Linus's tree.
>
> and in any case... can you avoid read_lock(tasklist) in alloc_pid() ?
> This is really not good.
I'm afraid I am totally confused, but it looks unnecessary.
Once ->child_reaper is set, it can be changed but not cleared.
This means that pidns_for_children_get() doesn't need tasklist too.
However. With or without this patch, we probably need WRITE_ONCE()
in find_child_reaper() and copy_process() + READ_ONCE() in alloc_pid()
to avoid the possible warnings from KCSAN.
No?
Oleg.
next prev parent reply other threads:[~2026-02-22 16:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-20 16:42 [PATCH 0/2] pid_namespace: make init creation more flexible Pavel Tikhomirov
2026-02-20 16:42 ` [PATCH 1/2] pid_namespace: allow opening pid_for_children before init was created Pavel Tikhomirov
2026-02-22 15:38 ` Oleg Nesterov
2026-02-22 16:41 ` Pavel Tikhomirov
2026-02-22 16:55 ` Oleg Nesterov [this message]
2026-02-23 17:24 ` Pavel Tikhomirov
2026-02-20 16:42 ` [PATCH 2/2] selftests: Add tests for creating pidns init via setns Pavel Tikhomirov
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