Re: [PATCH] pid: Add a judgment for ns null in pid_nr_ns

[Christian Brauner <brauner@kernel.org>]

On Sat, 02 Aug 2025 10:21:23 +0800, Xiang Gao wrote:
> __task_pid_nr_ns
>         ns = task_active_pid_ns(current);
>         pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
>                 if (pid && ns->level <= pid->level) {
> 
> Sometimes null is returned for task_active_pid_ns. Then it will trigger kernel panic in pid_nr_ns.
> 
> [...]

Applied to the vfs-6.18.pidfs branch of the vfs/vfs.git tree.
Patches in the vfs-6.18.pidfs branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.18.pidfs

[1/1] pid: Add a judgment for ns null in pid_nr_ns
      https://git.kernel.org/vfs/vfs/c/006568ab4c5c
[1/4] pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers
      https://git.kernel.org/vfs/vfs/c/abdfd4948e45
[3/4] pid: change bacct_add_tsk() to use task_ppid_nr_ns()
      https://git.kernel.org/vfs/vfs/c/b1afcaddd6c8
[4/4] pid: change task_state() to use task_ppid_nr_ns()
      https://git.kernel.org/vfs/vfs/c/d00f5232851c