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Date:   Fri, 24 Jun 2022 10:46:17 -0700
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Subject: Re: [PATCH bpf-next v2 3/8] bpf, iter: Fix the condition on p when
 calling stop.
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To:     Hao Luo <haoluo@google.com>
Cc:     Yosry Ahmed <yosryahmed@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Tejun Heo <tj@kernel.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Shuah Khan <shuah@kernel.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        David Rientjes <rientjes@google.com>,
        Stanislav Fomichev <sdf@google.com>,
        Greg Thelen <gthelen@google.com>,
        Shakeel Butt <shakeelb@google.com>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        bpf@vger.kernel.org, cgroups@vger.kernel.org
References: <20220610194435.2268290-1-yosryahmed@google.com>
 <20220610194435.2268290-4-yosryahmed@google.com>
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From:   Yonghong Song <yhs@fb.com>
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On 6/21/22 12:25 AM, Hao Luo wrote:
> On Mon, Jun 20, 2022 at 11:48 AM Yonghong Song <yhs@fb.com> wrote:
>>
>> On 6/10/22 12:44 PM, Yosry Ahmed wrote:
>>> From: Hao Luo <haoluo@google.com>
>>>
>>> In bpf_seq_read, seq->op->next() could return an ERR and jump to
>>> the label stop. However, the existing code in stop does not handle
>>> the case when p (returned from next()) is an ERR. Adds the handling
>>> of ERR of p by converting p into an error and jumping to done.
>>>
>>> Because all the current implementations do not have a case that
>>> returns ERR from next(), so this patch doesn't have behavior changes
>>> right now.
>>>
>>> Signed-off-by: Hao Luo <haoluo@google.com>
>>> Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
>>
>> Acked-by: Yonghong Song <yhs@fb.com>
> 
> Yonghong, do you want to get this change in now, or you want to wait
> for the whole patchset? This fix is straightforward and independent of
> other parts. Yosry and I can rebase.

Sorry for delay. Let me review other patches as well before your next 
version.

BTW, I would be great if you just put the prerequisite patch
 
https://lore.kernel.org/bpf/20220421140740.459558-5-benjamin.tissoires@redhat.com/
as the first patch so at least BPF CI will be able to test
your patch set. It looks like KP's bpf_getxattr patch set already did this.
 
https://lore.kernel.org/bpf/20220624045636.3668195-2-kpsingh@kernel.org/T/#u