From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Kumar Kartikeya Dwivedi" <memxor@gmail.com>
Cc: "Emil Tsalapatis" <emil@etsalapatis.com>, <bpf@vger.kernel.org>,
<andrii@kernel.org>, <eddyz87@gmail.com>, <daniel@iogearbox.net>,
"Tejun Heo" <tj@kernel.org>
Subject: Re: [PATCH bpf 1/2] bpf: recover page faults across all arenas
Date: Tue, 03 Nov 2026 01:47:22 +0000 [thread overview]
Message-ID: <DML73TNAFORF.67E0ZRLWONC@gmail.com> (raw)
In-Reply-To: <CAP01T77fBRqfCM=VVjq0Vo8zFYzBLL9Adw5Wr8ar-fb862L1RA@mail.gmail.com>
On Mon, Nov 02, 2026 at 03:35 PM Kumar Kartikeya Dwivedi <memxor@gmail.com> wrote:
>> > - prog = bpf_prog_find_from_stack();
>>
>> This has to stay. If there are thousands arena. Above should still be a fast path.
>> Only for sched-ext arena access it should search link link.
>
> We cannot rely on this, there might be a different program in the call
> stack. That's why there is an equality check on the arena when
> actually reporting, to make sure it's going to the right program.
I meant it as a fast path, not as the only path.
the equality check is needed, of course.
A different prog on the stack will fail that check and
the handler will do latch search.
next prev parent reply other threads:[~2026-11-03 1:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-28 1:51 [PATCH bpf-next 0/2] bpf: expand BPF arena kernel fault handling Emil Tsalapatis
2026-10-28 1:51 ` [PATCH bpf 1/2] bpf: recover page faults across all arenas Emil Tsalapatis
2026-10-28 2:36 ` bot+bpf-ci
2026-11-02 22:58 ` Alexei Starovoitov
2026-11-02 23:35 ` Kumar Kartikeya Dwivedi
2026-11-03 1:47 ` Alexei Starovoitov [this message]
2026-10-28 1:51 ` [PATCH bpf 2/2] selftests/bpf: add arena fault recovery tests Emil Tsalapatis
2026-10-28 2:13 ` sashiko-bot
2026-11-02 22:59 ` Alexei Starovoitov
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