Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7B15D57D20A; Wed, 9 Sep 2026 14:34:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788964495; cv=none; b=skIaQ6+Ugcz9fRd3G/8fi2jqoeIKCqeI8C8XvR4B/TEX+QuwWPWK+C0az9VY80XTdtcOZ5zKvD+SJisSp9QkoxrMh8FTMr2jB40HoaLhdfAihwGidYs0cDJN0GVUi9e40VZc0k1f/OIuUmBCT0ODtthMhvQcJAFDwH6v/saGfiU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788964495; c=relaxed/simple; bh=4bgnhyPSlP025Xkz358UOszXVEgFLVwZ/hj3AxjMfUs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e4YXTmvKlvStXcvJ/VkyLVWUcq3Fy0v5ovjKJJ+qRQGDXfiO/cd1FCt47VbPtiE37GzfF8GEI8srW0d3Q0vMI7QgLjPvNhiZ9Dwhli/frHCA7BMF2XZ6xR2pSOR6vffayGUxiYPL8LDHwfI+gP6GRLnpJ9/Hay6ju7P5FOPS6VM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=P9MkhUrP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="P9MkhUrP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D42991F00A3A; Wed, 9 Sep 2026 14:34:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788964494; bh=B/cd6Z+qez7zPFLlA2HosG2WM0givNgogGR7qWMt11c=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=P9MkhUrPvnBghI/kkOL8zDIAN76dAuOuOFFb9+78cDHqTe+0Y397NATMW428jDGlX n+aXsfY5iV39/lM9uKIQBjfS7Bd12c5zG4F5OWrbaaPSSRheidMWsN09I9v5ecSW/y haa+E1uYZp8jXfK9aQ9IXgl134tUuhUcTPoc/wOs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christian Brauner , Sasha Levin Subject: [PATCH 6.18 443/583] pidfs: simplify PIDFD_GET__NAMESPACE ioctls Date: Wed, 9 Sep 2026 15:42:08 +0200 Message-ID: <20260909134253.324449429@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260909134237.773280130@linuxfoundation.org> References: <20260909134237.773280130@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Brauner [ Upstream commit a71e4f103aed69e7a11ea913312726bb194c76ee ] We have reworked namespaces sufficiently that all this special-casing shouldn't be needed anymore Link: https://patch.msgid.link/20251117-eidesstattlich-apotheke-36d2e644079f@brauner Signed-off-by: Christian Brauner Stable-dep-of: 9688a4680293 ("pidfd: hold exec_update_lock around namespace ioctl") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/pidfs.c | 75 +++++++++++++++++++++++++++++-------------------------------- 1 file changed, 36 insertions(+), 39 deletions(-) --- a/fs/pidfs.c +++ b/fs/pidfs.c @@ -456,7 +456,6 @@ static long pidfd_ioctl(struct file *fil struct task_struct *task __free(put_task) = NULL; struct nsproxy *nsp __free(put_nsproxy) = NULL; struct ns_common *ns_common = NULL; - struct pid_namespace *pid_ns; if (!pidfs_ioctl_valid(cmd)) return -ENOIOCTLCMD; @@ -498,66 +497,64 @@ static long pidfd_ioctl(struct file *fil switch (cmd) { /* Namespaces that hang of nsproxy. */ case PIDFD_GET_CGROUP_NAMESPACE: - if (IS_ENABLED(CONFIG_CGROUPS)) { - get_cgroup_ns(nsp->cgroup_ns); - ns_common = to_ns_common(nsp->cgroup_ns); - } + if (!ns_ref_get(nsp->cgroup_ns)) + break; + ns_common = to_ns_common(nsp->cgroup_ns); break; case PIDFD_GET_IPC_NAMESPACE: - if (IS_ENABLED(CONFIG_IPC_NS)) { - get_ipc_ns(nsp->ipc_ns); - ns_common = to_ns_common(nsp->ipc_ns); - } + if (!ns_ref_get(nsp->ipc_ns)) + break; + ns_common = to_ns_common(nsp->ipc_ns); break; case PIDFD_GET_MNT_NAMESPACE: - get_mnt_ns(nsp->mnt_ns); + if (!ns_ref_get(nsp->mnt_ns)) + break; ns_common = to_ns_common(nsp->mnt_ns); break; case PIDFD_GET_NET_NAMESPACE: - if (IS_ENABLED(CONFIG_NET_NS)) { - ns_common = to_ns_common(nsp->net_ns); - get_net_ns(ns_common); - } + if (!ns_ref_get(nsp->net_ns)) + break; + ns_common = to_ns_common(nsp->net_ns); break; case PIDFD_GET_PID_FOR_CHILDREN_NAMESPACE: - if (IS_ENABLED(CONFIG_PID_NS)) { - get_pid_ns(nsp->pid_ns_for_children); - ns_common = to_ns_common(nsp->pid_ns_for_children); - } + if (!ns_ref_get(nsp->pid_ns_for_children)) + break; + ns_common = to_ns_common(nsp->pid_ns_for_children); break; case PIDFD_GET_TIME_NAMESPACE: - if (IS_ENABLED(CONFIG_TIME_NS)) { - get_time_ns(nsp->time_ns); - ns_common = to_ns_common(nsp->time_ns); - } + if (!ns_ref_get(nsp->time_ns)) + break; + ns_common = to_ns_common(nsp->time_ns); break; case PIDFD_GET_TIME_FOR_CHILDREN_NAMESPACE: - if (IS_ENABLED(CONFIG_TIME_NS)) { - get_time_ns(nsp->time_ns_for_children); - ns_common = to_ns_common(nsp->time_ns_for_children); - } + if (!ns_ref_get(nsp->time_ns_for_children)) + break; + ns_common = to_ns_common(nsp->time_ns_for_children); break; case PIDFD_GET_UTS_NAMESPACE: - if (IS_ENABLED(CONFIG_UTS_NS)) { - get_uts_ns(nsp->uts_ns); - ns_common = to_ns_common(nsp->uts_ns); - } + if (!ns_ref_get(nsp->uts_ns)) + break; + ns_common = to_ns_common(nsp->uts_ns); break; /* Namespaces that don't hang of nsproxy. */ case PIDFD_GET_USER_NAMESPACE: - if (IS_ENABLED(CONFIG_USER_NS)) { - rcu_read_lock(); - ns_common = to_ns_common(get_user_ns(task_cred_xxx(task, user_ns))); - rcu_read_unlock(); + scoped_guard(rcu) { + struct user_namespace *user_ns; + + user_ns = task_cred_xxx(task, user_ns); + if (!ns_ref_get(user_ns)) + break; + ns_common = to_ns_common(user_ns); } break; case PIDFD_GET_PID_NAMESPACE: - if (IS_ENABLED(CONFIG_PID_NS)) { - rcu_read_lock(); + scoped_guard(rcu) { + struct pid_namespace *pid_ns; + pid_ns = task_active_pid_ns(task); - if (pid_ns) - ns_common = to_ns_common(get_pid_ns(pid_ns)); - rcu_read_unlock(); + if (!ns_ref_get(pid_ns)) + break; + ns_common = to_ns_common(pid_ns); } break; default: