From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Yonghong Song" <yonghong.song@linux.dev>, <bpf@vger.kernel.org>
Cc: "Andrii Nakryiko" <andrii@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Eduard Zingerman" <eddyz87@gmail.com>, <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next v11 13/26] bpf: Allow a subprog to end with a call that does not return
Date: Fri, 16 Oct 2026 02:12:39 +0000 [thread overview]
Message-ID: <DM5WDDT1HM2C.BQULK4DXMUU2@gmail.com> (raw)
In-Reply-To: <20261015040250.860960-1-yonghong.song@linux.dev>
On Wed, Oct 14, 2026 at 09:02 PM Yonghong Song <yonghong.song@linux.dev> wrote:
> Let a call to a subprog or to a kfunc be the last insn of a subprog, and
> give it no fall-through edge in the CFG walk or in bpf_insn_successors().
[...]
> include/linux/bpf_verifier.h | 10 +++++
> kernel/bpf/backtrack.c | 6 ++-
> kernel/bpf/cfg.c | 5 +++
> kernel/bpf/liveness.c | 9 ++---
> kernel/bpf/verifier.c | 74 ++++++++++++++++++++++++++++++------
> 5 files changed, 85 insertions(+), 19 deletions(-)
This is quite heavy.
keep_subprog_exits() in the previous patch adds 'exit' after the last
insn with bpf_patch_insn_data().
Can we do the same for a subprog that ends with a call
before bpf_check_cfg() ?
Then cfg, liveness, backtracking, fastcall and prepare_func_exit()
don't need to know about it. Only the check_subprogs() hunk stays.
next prev parent reply other threads:[~2026-10-16 2:12 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-15 4:01 [PATCH bpf-next v11 00/26] bpf: Run exception cleanup landing pads when bpf_unwind() unwinds Yonghong Song
2026-10-15 4:01 ` [PATCH bpf-next v11 01/26] bpf: Pack bpf_insn_aux_data flags into bit fields Yonghong Song
2026-10-15 4:01 ` [PATCH bpf-next v11 02/26] bpf: Accept the compiler's exception cleanup table at program load Yonghong Song
2026-10-15 4:01 ` [PATCH bpf-next v11 03/26] bpf: Add the bpf_unwind() and bpf_unwind_resume() kfuncs Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 04/26] bpf: Keep a call site's landing pad in insn_aux_data, add lookups Yonghong Song
2026-10-15 4:16 ` sashiko-bot
2026-10-15 15:19 ` Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 05/26] bpf: Mark covered call sites and check a program can take a table Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 06/26] bpf: Make exception landing pads reachable in the CFG Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 07/26] bpf: Verify an unwind through landing pads and epilogues Yonghong Song
2026-10-15 4:29 ` sashiko-bot
2026-10-15 15:43 ` Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 08/26] bpf: Refuse a callback that can unwind Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 09/26] bpf: Refuse a landing pad that does not resume Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 10/26] bpf: Do not use a private stack for a program that can unwind Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 11/26] bpf: Prepare JITed programs for dispatching cleanup pads Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 12/26] bpf: Keep an epilogue for each subprog an unwind can pass through Yonghong Song
2026-10-15 4:02 ` [PATCH bpf-next v11 13/26] bpf: Allow a subprog to end with a call that does not return Yonghong Song
2026-10-16 2:12 ` Alexei Starovoitov [this message]
2026-10-15 4:02 ` [PATCH bpf-next v11 14/26] bpf: Dispatch cleanup pads by rewriting return addresses Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 15/26] bpf: Refuse a trampoline that calls a subprog that can unwind Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 16/26] bpf, x86: Dispatch exception cleanup pads at run time Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 17/26] bpf, arm64: " Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 18/26] libbpf: Resolve the compiler's _Unwind_Resume to the kernel's kfunc Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 19/26] libbpf: Add cleanup_info to bpf_prog_load_opts Yonghong Song
2026-10-15 4:13 ` sashiko-bot
2026-10-15 15:45 ` Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 20/26] libbpf: Collect .bpf_cleanup records and pass them to the kernel Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 21/26] libbpf: Carry the exception cleanup table through the light skeleton Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 22/26] libbpf: Let the static linker carry .bpf_cleanup relocations Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 23/26] selftests/bpf: Add end-to-end and negative .bpf_cleanup exception tests Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 24/26] selftests/bpf: Add __set_global() and __ret_global() test tags Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 25/26] selftests/bpf: Cover more accepted .bpf_cleanup exception shapes Yonghong Song
2026-10-15 4:03 ` [PATCH bpf-next v11 26/26] selftests/bpf: Load an exception cleanup program from a light skeleton Yonghong Song
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