From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Ihor Solodrai" <ihor.solodrai@linux.dev>,
<patchwork-bot+netdevbpf@kernel.org>
Cc: <bpf@vger.kernel.org>, <daniel@iogearbox.net>,
<andrii@kernel.org>, <eddyz87@gmail.com>, <memxor@gmail.com>,
"Emil Tsalapatis" <emil@etsalapatis.com>
Subject: Re: [PATCH bpf-next v2 00/17] bpf: Indirect calls of bpf subprogs (callx)
Date: Tue, 29 Sep 2026 06:04:47 +0000 [thread overview]
Message-ID: <DLRKNUWD51KM.3URQDVOWL0BRY@gmail.com> (raw)
In-Reply-To: <a25b9150-55ba-41ef-8de9-0067b4576278@linux.dev>
On Mon, Sep 28, 2026 at 04:13 PM Ihor Solodrai <ihor.solodrai@linux.dev> wrote:
> We're testing clang 21->22 bump on BPF CI, and something is broken
> when compiling callx selftests:
>
> 2026-09-28T22:12:12.4226025Z error: Undefined temporary symbol
> .Lswitch.table.call_by_switch
That's a bug in llvm 22. Not related to callx.
With -mcpu=v4 BPFAsmPrinter::doFinalization() is supposed to remove
private arrays of blockaddress that were converted to gotox jump tables,
but it removes all private const arrays of pointers.
clang turns the switch in call_by_switch() into such array of
pointers to functions.
Yonghong fixed it in llvm 23:
commit 9fc458a1d95b ("[BPF] Fix erroneous removal of non-jump-table globals")
It landed after 22.1.8, so no release of 22 has it.
> What's the requirements for callx? Does it need bleeding edge clang?
> If so, let's explicitly skip relevant selftests for clang < N?
No. clang generates callx for years. clang 21 is fine and 22 is fine
with v2 and v3.
I'd bump CI to clang 23.
A bunch of other tests require __clang_major__ >= 23 already.
next prev parent reply other threads:[~2026-09-29 6:04 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-24 3:10 [PATCH bpf-next v2 00/17] bpf: Indirect calls of bpf subprogs (callx) Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 01/17] bpf: Fix infinite loop in check_max_stack_depth() Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 02/17] selftests/bpf: Test recursion through a global function and a callback Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 03/17] bpf: Keep functions with address taken when removing dead code Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 04/17] bpf: Prepare static analysis passes for callx instruction Alexei Starovoitov
2026-09-24 3:56 ` bot+bpf-ci
2026-09-24 4:18 ` Eduard Zingerman
2026-09-24 3:10 ` [PATCH bpf-next v2 05/17] bpf: Add callx instruction to call bpf subprogs indirectly Alexei Starovoitov
2026-09-24 3:28 ` sashiko-bot
2026-09-24 3:10 ` [PATCH bpf-next v2 06/17] bpf: Add callx calls to the call graph Alexei Starovoitov
2026-09-24 3:26 ` sashiko-bot
2026-09-24 3:56 ` bot+bpf-ci
2026-09-24 5:00 ` Eduard Zingerman
2026-09-24 3:10 ` [PATCH bpf-next v2 07/17] bpf, x86: Add JIT support for callx Alexei Starovoitov
2026-09-24 5:33 ` Eduard Zingerman
2026-09-24 3:10 ` [PATCH bpf-next v2 08/17] bpf, arm64: " Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 09/17] bpf: Discover subprogs described by func_info Alexei Starovoitov
2026-09-24 5:42 ` Eduard Zingerman
2026-09-24 3:10 ` [PATCH bpf-next v2 10/17] bpf: Recognize pointers to functions in read-only maps Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 11/17] libbpf: Support pointers to static functions in data when linking Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 12/17] libbpf: Resolve pointers to functions in read-only data Alexei Starovoitov
2026-09-24 3:27 ` sashiko-bot
2026-09-24 3:10 ` [PATCH bpf-next v2 13/17] libbpf: Treat .data.rel.ro as " Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 14/17] libbpf: Support pointers to functions in read-only data in light skeleton Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 15/17] selftests/bpf: Add tests for callx Alexei Starovoitov
2026-09-24 3:56 ` bot+bpf-ci
2026-09-24 3:10 ` [PATCH bpf-next v2 16/17] selftests/bpf: Add tests for callx through pointers in read-only data Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 17/17] bpf, docs: Document callx instruction Alexei Starovoitov
2026-09-24 5:50 ` [PATCH bpf-next v2 00/17] bpf: Indirect calls of bpf subprogs (callx) patchwork-bot+netdevbpf
2026-09-24 5:55 ` Eduard Zingerman
2026-09-24 6:00 ` Alexei Starovoitov
2026-09-24 17:50 ` Ihor Solodrai
2026-09-24 18:09 ` Alexei Starovoitov
2026-09-28 23:13 ` Ihor Solodrai
2026-09-29 6:04 ` Alexei Starovoitov [this message]
2026-09-29 16:40 ` Ihor Solodrai
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=DLRKNUWD51KM.3URQDVOWL0BRY@gmail.com \
--to=alexei.starovoitov@gmail.com \
--cc=andrii@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=eddyz87@gmail.com \
--cc=emil@etsalapatis.com \
--cc=ihor.solodrai@linux.dev \
--cc=memxor@gmail.com \
--cc=patchwork-bot+netdevbpf@kernel.org \
/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.