On Thu, Nov 17, 2022 at 06:21:00PM -0800, Alexei Starovoitov wrote:
[...]
> > +static inline int tasks_kfunc_map_insert(struct task_struct *p)
> > +{
> > + struct __tasks_kfunc_map_value local, *v;
> > + long status;
> > + struct task_struct *acquired, *old;
> > + s32 pid;
> > +
> > + status = bpf_probe_read_kernel(&pid, sizeof(pid), &p->pid);
> > + if (status)
> > + return status;
> > +
> > + local.task = NULL;
> > + status = bpf_map_update_elem(&__tasks_kfunc_map, &pid, &local, BPF_NOEXIST);
> > + if (status)
> > + return status;
> > +
> > + v = bpf_map_lookup_elem(&__tasks_kfunc_map, &pid);
> > + if (!v) {
> > + bpf_map_delete_elem(&__tasks_kfunc_map, &pid);
> > + return status;
>
> here it will return 0, but probably should be returning error?
Ah, yes this should be returning -ENOENT. Thanks for catching this.
[...]
> > +SEC("tp_btf/task_newtask")
> > +int BPF_PROG(task_kfunc_release_null, struct task_struct *task, u64 clone_flags)
> > +{
> > + struct __tasks_kfunc_map_value local, *v;
> > + long status;
> > + struct task_struct *acquired, *old;
> > + s32 pid;
> > +
> > + status = bpf_probe_read_kernel(&pid, sizeof(pid), &task->pid);
> > + if (status)
> > + return 0;
> > +
> > + local.task = NULL;
> > + status = bpf_map_update_elem(&__tasks_kfunc_map, &pid, &local, BPF_NOEXIST);
> > + if (status)
> > + return status;
> > +
> > + v = bpf_map_lookup_elem(&__tasks_kfunc_map, &pid);
> > + if (!v)
> > + return status;
>
> should be return error instead?
Yep, here as well.
I'll fix both of these in v8.
[...]
