Re: [PATCH v3 1/1] bpf: Drop unprotected find_vpid() in favour of find_get_pid()

[Lee Jones]

On Thu, 08 Sep 2022, Lee Jones wrote:

> On Tue, 09 Aug 2022, Lee Jones wrote:
> 
> > The documentation for find_vpid() clearly states:
> > 
> >   "Must be called with the tasklist_lock or rcu_read_lock() held."
> > 
> > Presently we do neither.
> > 
> > Let's use find_get_pid() which searches for the vpid, then takes a
> > reference to it preventing early free, all within the safety of
> > rcu_read_lock().  Once we have our reference we can safely make use of
> > it up until the point it is put.
> > 
> > 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")
> > Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
> > ---
> > 
> > v1 => v2:
> >   * Commit log update - description - no code differences
> > 
> > v2 => v3:
> >   * Commit log update - spelling of find_vpid() - no code differences
> 
> Did anyone get a chance to look at this please?
> 
> Would you like a [RESEND]?

Scrap that.  I've just seen the last replies to v2.

Leave it with me.

-- 
Lee Jones [李琼斯]