Re: [PATCH v3 1/1] bpf: Ensure correct locking around vulnerable function find_vpid()

[Yonghong Song]

On 9/12/22 4:14 PM, Lee Jones wrote:
> On Mon, 12 Sep 2022, Yonghong Song wrote:
> > On 9/12/22 2:38 PM, Lee Jones wrote:
> > > The documentation for find_vpid() clearly states:
> >
> > No need for the above extra line.
>
> The intentional blank formatting line?
>
> The commit message would look worse without it.
>
> Is this really a blocker?

Not a blocker. Just a suggestion. I won't enforce it
if you do have this extra line.

> > >     "Must be called with the tasklist_lock or rcu_read_lock() held."
> > >
> > > Presently we do neither.
> >
> > Presently we do neither for find_vpid() instance in bpf_task_fd_query().
> > Add proper rcu_read_lock/unlock() to fix the issue.
>
> I can expand this.
>
> > > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > > Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> > > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > > Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> > > Cc: Andrii Nakryiko <andrii@xxxxxxxxxx>
> > > Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx>
> > > Cc: Song Liu <song@xxxxxxxxxx>
> > > Cc: Yonghong Song <yhs@xxxxxx>
> > > Cc: KP Singh <kpsingh@xxxxxxxxxx>
> > > Cc: Stanislav Fomichev <sdf@xxxxxxxxxx>
> > > Cc: Hao Luo <haoluo@xxxxxxxxxx>
> > > Cc: bpf@xxxxxxxxxxxxxxx
> > > Fixes: 41bdc4b40ed6f ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY")
> > > Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
> >
> > Ack with above a few suggestions for the commit message.
> >
> > Acked-by: Yonghong Song <yhs@xxxxxx>