From: Jay Wang <wanjay@amazon.com>
To: <sashiko-bot@kernel.org>
Cc: <bpf@vger.kernel.org>, <linux-modules@vger.kernel.org>,
<ojeda@kernel.org>, <gary@garyguo.net>
Subject: Re: [PATCH bpf-next v3 3/9] bpf: fetch the vmlinux BTF where kernel types enter a program
Date: Thu, 1 Oct 2026 23:51:27 +0000 [thread overview]
Message-ID: <20261001235127.4111-1-wanjay@amazon.com> (raw)
In-Reply-To: <20260925231100.6A2481F00893@smtp.kernel.org>
The scenario does not happen; v4 keeps this behaviour:
https://lore.kernel.org/bpf/20261001225214.12351-1-wanjay@amazon.com/
With CONFIG_DEBUG_INFO_BTF=m an allocation failure of the parse is not
stored: bpf_load_btf_vmlinux(), which parses the BTF in v4, returns the
error without publishing it, btf_vmlinux stays NULL, the next request
retries, and this check does not fire for anyone. What v4 does store
with =m, as a later bpf-ci review asked, is a parse failure for any
other reason. The payload was checked against the kernel's size and
SHA-256 when btf_vmlinux.ko loaded, so that means the build produced a
broken BTF. The same happens with =y, where upstream already fails
every later bpf_check() with this message.
With =y the parse happens at boot, through the first vmlinux kfunc
registration, as it does today.
Jay
next prev parent reply other threads:[~2026-10-01 23:51 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-25 22:42 [PATCH bpf-next v3 0/9] bpf: make the vmlinux BTF an on-demand loadable module (CONFIG_DEBUG_INFO_BTF=m) to save ~5.4 MB memory Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 1/9] bpf: pass the vmlinux BTF to btf_parse_module() and let it adopt the data Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 2/9] bpf: split the kfunc, dtor kfunc and struct_ops registration bodies Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 3/9] bpf: fetch the vmlinux BTF where kernel types enter a program Jay Wang
2026-09-25 23:10 ` sashiko-bot
2026-10-01 23:51 ` Jay Wang [this message]
2026-09-25 22:42 ` [PATCH bpf-next v3 4/9] bpf: take the vmlinux BTF from the btf_vmlinux module Jay Wang
2026-09-25 23:23 ` bot+bpf-ci
2026-10-01 23:51 ` Jay Wang
2026-09-26 8:29 ` Alexei Starovoitov
2026-10-01 23:51 ` Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 5/9] bpf: defer vmlinux kfunc and struct_ops registrations Jay Wang
2026-09-25 23:34 ` bot+bpf-ci
2026-10-01 23:52 ` Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 6/9] bpf: keep module BTF until the vmlinux BTF is available Jay Wang
2026-09-25 22:59 ` sashiko-bot
2026-10-01 23:52 ` Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 7/9] bpf: expose deferred .BTF.base module BTF in sysfs from module load Jay Wang
2026-09-25 23:23 ` bot+bpf-ci
2026-10-01 23:52 ` Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 8/9] bpf, trace, net: prepare CONFIG_DEBUG_INFO_BTF checks for a tristate Jay Wang
2026-09-25 23:23 ` bot+bpf-ci
2026-10-01 23:53 ` Jay Wang
2026-09-25 22:42 ` [PATCH bpf-next v3 9/9] kbuild, bpf: allow building the vmlinux BTF as a module Jay Wang
2026-09-25 23:34 ` bot+bpf-ci
2026-10-01 23:53 ` Jay Wang
2026-09-28 10:00 ` Alan Maguire
[not found] ` <DM6PR18MB2666F6B235D5B356AA157A7DA98D2@DM6PR18MB2666.namprd18.prod.outlook.com>
2026-09-29 18:25 ` Alan Maguire
2026-10-01 23:53 ` Jay Wang
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