Re: [PATCH bpf v2 1/3] bpf: Pin iterator link when opening iterator

[Yonghong Song <yhs@meta.com>]

On 11/10/22 10:34 PM, Hou Tao wrote:
> From: Hou Tao <houtao1@huawei.com>
> 
> For many bpf iterator (e.g., cgroup iterator), iterator link acquires
> the reference of iteration target in .attach_target(), but iterator link
> may be closed before or in the middle of iteration, so iterator will
> need to acquire the reference of iteration target as well to prevent
> potential use-after-free. To avoid doing the acquisition in
> .init_seq_private() for each iterator type, just pin iterator link in
> iterator.
> 
> Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter")
> Signed-off-by: Hou Tao <houtao1@huawei.com>

Thanks. LGTM. Once this patch went through bpf and circulated back to
bpf-next, you can revert the change for the following patches:
    f0d2b2716d71  bpf: Acquire map uref in .init_seq_private for 
sock{map,hash} iterator
    3c5f6e698b5c  bpf: Acquire map uref in .init_seq_private for sock 
local storage map iterator
    ef1e93d2eeb5  bpf: Acquire map uref in .init_seq_private for hash 
map iterator
    f76fa6b33805  bpf: Acquire map uref in .init_seq_private for array 
map iterator
in bpf-next.

Acked-by: Yonghong Song <yhs@fb.com>