From: Eduard Zingerman <eddyz87@gmail.com>
To: Yonghong Song <yonghong.song@linux.dev>, bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
kernel-team@fb.com
Subject: Re: [PATCH bpf-next v5 12/21] bpf, x86: Dispatch exception cleanup pads at run time
Date: Tue, 22 Sep 2026 23:45:30 -0700 [thread overview]
Message-ID: <a47eb8c7aa3c9806b2a4e01554f5c6daa3fa9f6c.camel@gmail.com> (raw)
In-Reply-To: <20260923045948.2420512-1-yonghong.song@linux.dev>
On Tue, 2026-09-22 at 21:59 -0700, Yonghong Song wrote:
...
> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index d4a980140b48..26df52050cd7 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
...
> @@ -2024,7 +2034,7 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
> /* Exception callback will clobber callee regs for its own use, and
> * restore the original callee regs from main prog's stack frame.
> */
> - if (bpf_prog->aux->exception_boundary) {
> + if (bpf_prog->aux->exception_boundary || bpf_exc_force_spill(bpf_prog)) {
On option to avoid spilling all the registers would be to use register
liveness information at call sites and collect a union of registers
alive at landing pads for all callers of this particular function.
Wdyt?
> /* We also need to save r12, which is not mapped to any BPF
> * register, as we throw after entry into the kernel, which may
> * overwrite r12.
...
next prev parent reply other threads:[~2026-09-23 6:45 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-23 4:58 [PATCH bpf-next v5 00/21] bpf: Run exception cleanup landing pads when bpf_throw() unwinds Yonghong Song
2026-09-23 4:58 ` [PATCH bpf-next v5 01/21] bpf: Pack bpf_insn_aux_data flags into bit fields Yonghong Song
2026-09-23 5:40 ` bot+bpf-ci
2026-09-23 19:16 ` Eduard Zingerman
2026-09-23 4:58 ` [PATCH bpf-next v5 02/21] bpf: Accept the compiler's exception cleanup table at program load Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 03/21] bpf: Add the bpf_unwind_resume() kfunc Yonghong Song
2026-09-23 6:13 ` Kumar Kartikeya Dwivedi
2026-09-23 4:59 ` [PATCH bpf-next v5 04/21] bpf: Add lookups for exception cleanup resumes and landing pads Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 05/21] bpf: Prepare for an exception cleanup table before the CFG walk Yonghong Song
2026-09-23 5:40 ` bot+bpf-ci
2026-09-23 4:59 ` [PATCH bpf-next v5 06/21] bpf: Make exception landing pads reachable in the CFG Yonghong Song
2026-09-23 5:51 ` bot+bpf-ci
2026-09-23 19:25 ` Eduard Zingerman
2026-09-23 4:59 ` [PATCH bpf-next v5 07/21] bpf: Explore the landing pads no call site reaches Yonghong Song
2026-09-23 16:26 ` Eduard Zingerman
2026-09-23 17:27 ` Yonghong Song
2026-09-23 18:06 ` Eduard Zingerman
2026-09-23 18:09 ` Yonghong Song
2026-09-23 21:28 ` Alexei Starovoitov
2026-09-23 22:19 ` Eduard Zingerman
2026-09-23 23:20 ` Alexei Starovoitov
2026-09-24 0:13 ` Kumar Kartikeya Dwivedi
2026-09-24 1:53 ` Alexei Starovoitov
2026-09-24 6:12 ` Kumar Kartikeya Dwivedi
2026-09-23 23:09 ` Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 08/21] bpf: Walk the exception unwind in the verifier Yonghong Song
2026-09-23 16:34 ` Eduard Zingerman
2026-09-23 18:01 ` Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 09/21] bpf: Refuse exception cleanup shapes bpf_throw() cannot dispatch Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 10/21] bpf: Refuse a private stack for a program with an exception cleanup table Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 11/21] bpf: Dispatch exception cleanup pads from bpf_throw() Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 12/21] bpf, x86: Dispatch exception cleanup pads at run time Yonghong Song
2026-09-23 6:45 ` Eduard Zingerman [this message]
2026-09-23 20:45 ` Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 13/21] bpf, arm64: " Yonghong Song
2026-09-23 4:59 ` [PATCH bpf-next v5 14/21] libbpf: Resolve the compiler's _Unwind_Resume to the kernel's kfunc Yonghong Song
2026-09-23 8:36 ` Kumar Kartikeya Dwivedi
2026-09-23 5:00 ` [PATCH bpf-next v5 15/21] libbpf: Add cleanup_info to bpf_prog_load_opts Yonghong Song
2026-09-23 5:00 ` [PATCH bpf-next v5 16/21] libbpf: Collect .bpf_cleanup records and pass them to the kernel Yonghong Song
2026-09-23 5:52 ` Kumar Kartikeya Dwivedi
2026-09-23 5:00 ` [PATCH bpf-next v5 17/21] libbpf: Carry the exception cleanup table through the light skeleton Yonghong Song
2026-09-23 5:00 ` [PATCH bpf-next v5 18/21] libbpf: Let the static linker carry .bpf_cleanup relocations Yonghong Song
2026-09-23 5:40 ` bot+bpf-ci
2026-09-23 5:00 ` [PATCH bpf-next v5 19/21] selftests/bpf: Add an end-to-end .bpf_cleanup exception test Yonghong Song
2026-09-23 5:51 ` bot+bpf-ci
2026-09-23 5:00 ` [PATCH bpf-next v5 20/21] selftests/bpf: Cover the exception cleanup shapes the chain does not reach Yonghong Song
2026-09-23 5:51 ` bot+bpf-ci
2026-09-23 7:50 ` Eduard Zingerman
2026-09-23 5:00 ` [PATCH bpf-next v5 21/21] selftests/bpf: Load an exception cleanup program from a light skeleton Yonghong Song
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=a47eb8c7aa3c9806b2a4e01554f5c6daa3fa9f6c.camel@gmail.com \
--to=eddyz87@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=kernel-team@fb.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox