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

[Qing Wang]

On Sat, 02 Aug 2025 at 10:21, Xiang Gao <gxxa03070307@xxxxxxxxx> 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) {

Hi,

There was a bug report about the UAF(tsk->signal) in __task_pid_nr_ns, and I'm
not sure whether it's related to this issue you're discussing. What do you
think?

[syzbot] [perf?] KASAN: slab-use-after-free Read in __task_pid_nr_ns
https://syzkaller.appspot.com/bug?extid=e0378d4f4fe57aa2bdd0

Qing.