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

[Yonghong Song]

On 9/12/22 2:38 PM, Lee Jones wrote:
> The documentation for find_vpid() clearly states:

No need for the above 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.

> 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>