From: Eduard Zingerman <eddyz87@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Hou Tao <houtao@huaweicloud.com>
Cc: bpf@vger.kernel.org, Martin KaFai Lau <martin.lau@linux.dev>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
Hao Luo <haoluo@google.com>,
Yonghong Song <yonghong.song@linux.dev>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>,
Jiri Olsa <jolsa@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
houtao1@huawei.com, xukuohai@huawei.com
Subject: Re: [PATCH bpf] bpf: Extend the size of scratched_stack_slots to 128 bits
Date: Wed, 23 Oct 2024 10:13:09 -0700 [thread overview]
Message-ID: <31d0895a217388dfe6bfa5b74c4b346705f894e4.camel@gmail.com> (raw)
In-Reply-To: <42a4ec6bccc867d18033583b1dfea0736ac1afb0.camel@gmail.com>
On Wed, 2024-10-23 at 09:17 -0700, Eduard Zingerman wrote:
[...]
> > We have other places where we assume that 64 bits is enough to specify
> > stack slot index (linked regs, for instance). Do we need to update all
> > of those now as well? If yes, maybe then it's better to make sure
> > valid programs can never go beyond 512 bytes of stack even for
> > bpf_fastcall?..
>
> Specifically function frames.
> This is a huge blunder from my side.
The following places are problematic:
- bpf_jmp_history_entry->flags
- backtrack_state->stack_masks
The following should be fine:
- bpf_func_state->stack
Not sure if anything else is affected (excluding scratched_stack_slots).
I agree that we either need to update backtracking logic,
or drop this stack extension logic.
next prev parent reply other threads:[~2024-10-23 17:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-23 2:27 [PATCH bpf] bpf: Extend the size of scratched_stack_slots to 128 bits Hou Tao
2024-10-23 16:15 ` Andrii Nakryiko
2024-10-23 16:17 ` Eduard Zingerman
2024-10-23 17:13 ` Eduard Zingerman [this message]
2024-10-23 17:33 ` Andrii Nakryiko
2024-10-23 17:37 ` Eduard Zingerman
2024-10-23 17:44 ` Andrii Nakryiko
2024-10-23 18:02 ` Eduard Zingerman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=31d0895a217388dfe6bfa5b74c4b346705f894e4.camel@gmail.com \
--to=eddyz87@gmail.com \
--cc=alexei.starovoitov@gmail.com \
--cc=andrii.nakryiko@gmail.com \
--cc=andrii@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=haoluo@google.com \
--cc=houtao1@huawei.com \
--cc=houtao@huaweicloud.com \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=kpsingh@kernel.org \
--cc=martin.lau@linux.dev \
--cc=sdf@fomichev.me \
--cc=song@kernel.org \
--cc=xukuohai@huawei.com \
--cc=yonghong.song@linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.