From: Breno Leitao <leitao@debian.org>
To: Kuniyuki Iwashima <kuniyu@google.com>
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>,
acme@kernel.org, netdev@vger.kernel.org, llvm@lists.linux.dev,
ast@kernel.org, yonghong.song@linux.dev, bpf@vger.kernel.org,
kuba@kernel.org, tj@kernel.org
Subject: Re: [BUG] bpf: tcp: bpf_tcp_ops_set_rcvlowat() missing from BTF with clang KCSAN
Date: Mon, 9 Nov 2026 04:33:40 -0800 [thread overview]
Message-ID: <avG9bk0kxRUvonhD@gmail.com> (raw)
In-Reply-To: <au4kpSGVSH3tYiZm@google.com>
On Fri, Nov 06, 2026 at 07:05:25PM +0000, Kuniyuki Iwashima wrote:
> On Fri, 06 Nov 2026 07:58:01 -0800, Breno Leitao wrote:
> > On Fri, Nov 06, 2026 at 09:16:24PM +0800, Jiayuan Chen wrote:
> > > Thanks for the report !
> > >
> > >
> > > On 11/6/26 7:38 PM, Breno Leitao wrote:
> > > > My arm64 KCSAN builds of linux-next fail since next-20261015, because
> > > > bpf_tcp_ops_set_rcvlowat() is missing from the vmlinux BTF:
> > > >
> > > > WARN: resolve_btfids: no BTF func for kfunc bpf_tcp_ops_set_rcvlowat in bpf_tcp_ops_set_rcvlowat_kfunc_set
> > > > WARN: resolve_btfids: unresolved symbol bpf_tcp_ops_set_rcvlowat
> > > > Failed to generate BTF for vmlinux
> > > > Try to disable CONFIG_DEBUG_INFO_BTF
> > > > make[4]: *** [scripts/Makefile.vmlinux:72: vmlinux.unstripped] Error 1
> > >
> > >
> > >
> > > Has pahole fixed this issue?
> >
> > I don't think so, see the line below:
>
> Could you try this ?
Thanks, it fixes my build. I tested it on top of pahole master (9eb594d)
with next-20261105 and clang 22.1.3:
- arm64 KCSAN, CONFIG_WERROR=y: vmlinux links again,
bpf_tcp_ops_set_rcvlowat() is back in BTF, __bpf_tcp_ops_init()
returns 0, and progs/tcp_autolowat.c from the selftests loads.
- It also brings back scx_bpf_tid_to_task() that was work arounded by
tejun.
Feel free to add my "Tested-by: Breno Leitao <leitao@debian.org>" tag.
--breno
next prev parent reply other threads:[~2026-11-09 12:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-06 11:38 [BUG] bpf: tcp: bpf_tcp_ops_set_rcvlowat() missing from BTF with clang KCSAN Breno Leitao
2026-11-06 13:16 ` Jiayuan Chen
2026-11-06 15:58 ` Breno Leitao
2026-11-06 19:05 ` Kuniyuki Iwashima
2026-11-09 12:33 ` Breno Leitao [this message]
2026-11-09 17:51 ` Arnaldo Carvalho de Melo
2026-11-10 5:40 ` netdev-bot+sashiko
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