linux-kernel - [PATCH bpf-next v2 0/3] Allow mmap of /sys/kernel/btf/vmlinux

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250502-vmlinux-mmap-v2-0-95c271434519@isovalent.com>
Date: Fri, 02 May 2025 11:20:04 +0100
From: Lorenz Bauer <lmb@...valent.com>
To: Arnd Bergmann <arnd@...db.de>, Alexei Starovoitov <ast@...nel.org>, 
 Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>, 
 Martin KaFai Lau <martin.lau@...ux.dev>, 
 Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>, 
 Yonghong Song <yonghong.song@...ux.dev>, 
 John Fastabend <john.fastabend@...il.com>, KP Singh <kpsingh@...nel.org>, 
 Stanislav Fomichev <sdf@...ichev.me>, Hao Luo <haoluo@...gle.com>, 
 Jiri Olsa <jolsa@...nel.org>, Mykola Lysenko <mykolal@...com>, 
 Shuah Khan <shuah@...nel.org>
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org, 
 bpf@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 Lorenz Bauer <lmb@...valent.com>
Subject: [PATCH bpf-next v2 0/3] Allow mmap of /sys/kernel/btf/vmlinux

I'd like to cut down the memory usage of parsing vmlinux BTF in ebpf-go.
With some upcoming changes the library is sitting at 5MiB for a parse.
Most of that memory is simply copying the BTF blob into user space.
By allowing vmlinux BTF to be mmapped read-only into user space I can
cut memory usage by about 75%.

Signed-off-by: Lorenz Bauer <lmb@...valent.com>
---
Changes in v2:
- Use btf__new in selftest
- Avoid vm_iomap_memory in btf_vmlinux_mmap
- Add VM_DONTDUMP
- Add support to libbpf
- Link to v1: https://lore.kernel.org/r/20250501-vmlinux-mmap-v1-0-aa2724572598@isovalent.com

---
Lorenz Bauer (3):
      btf: allow mmap of vmlinux btf
      selftests: bpf: add a test for mmapable vmlinux BTF
      libbpf: Use mmap to parse vmlinux BTF from sysfs

 include/asm-generic/vmlinux.lds.h                  |  3 +-
 kernel/bpf/sysfs_btf.c                             | 36 +++++++++-
 tools/lib/bpf/btf.c                                | 82 +++++++++++++++++++---
 tools/testing/selftests/bpf/prog_tests/btf_sysfs.c | 82 ++++++++++++++++++++++
 4 files changed, 189 insertions(+), 14 deletions(-)
---
base-commit: 38d976c32d85ef12dcd2b8a231196f7049548477
change-id: 20250501-vmlinux-mmap-2ec5563c3ef1

Best regards,
-- 
Lorenz Bauer <lmb@...valent.com>