From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: Christian Brauner <brauner@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.18.y 1/2] pidfs: simplify PIDFD_GET_<type>_NAMESPACE ioctls
Date: Thu, 3 Sep 2026 08:22:35 -0400 [thread overview]
Message-ID: <20260903122236.709194-1-sashal@kernel.org> (raw)
In-Reply-To: <2026090328-fleshed-scrambler-e1f2@gregkh>
From: Christian Brauner <brauner@kernel.org>
[ 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 <brauner@kernel.org>
Stable-dep-of: 9688a4680293 ("pidfd: hold exec_update_lock around namespace ioctl")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/pidfs.c | 75 ++++++++++++++++++++++++++----------------------------
1 file changed, 36 insertions(+), 39 deletions(-)
diff --git a/fs/pidfs.c b/fs/pidfs.c
index 34987fcdd9a87..7282ac3db0795 100644
--- a/fs/pidfs.c
+++ b/fs/pidfs.c
@@ -456,7 +456,6 @@ static long pidfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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 *file, unsigned int cmd, unsigned long arg)
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:
--
2.53.0
next prev parent reply other threads:[~2026-09-03 12:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-03 9:56 FAILED: patch "[PATCH] pidfd: hold exec_update_lock around namespace ioctl" failed to apply to 6.18-stable tree gregkh
2026-09-03 12:22 ` Sasha Levin [this message]
2026-09-03 12:22 ` [PATCH 6.18.y 2/2] pidfd: hold exec_update_lock around namespace ioctl Sasha Levin
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