linux.git/kernel/bpf/preload, branch v6.1.168

bpf/preload: Don't select USERMODE_DRIVER

2025-08-15T10:05:00+00:00

[ Upstream commit 2b03164eee20eac7ce0fe3aa4fbda7efc1e5427a ]

The usermode driver framework is not used anymore by the BPF
preload code.

Fixes: cb80ddc67152 ("bpf: Convert bpf_preload.ko to use light skeleton.")
Signed-off-by: Thomas Weißschuh 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/bpf/20250721-remove-usermode-driver-v1-1-0d0083334382@linutronix.de
Signed-off-by: Sasha Levin

bpf: iterators: Build and use lightweight bootstrap version of bpftool

2022-07-15T19:01:30+00:00

kernel/bpf/preload/iterators use bpftool for vmlinux.h, skeleton, and
static linking only. So we can use lightweight bootstrap version of
bpftool to handle these, and it will be faster.

Suggested-by: Andrii Nakryiko 
Signed-off-by: Pu Lehui 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20220714024612.944071-4-pulehui@huawei.com

bpf: Remove redundant slash

2022-03-08T06:19:32+00:00

The trailing slash of LIBBPF_SRCS is redundant, remove it. Also inline
it as its only used in LIBBPF_INCLUDE.

Signed-off-by: Yuntao Wang 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20220305161013.361646-1-ytcoode@gmail.com

bpf: Fix issue with bpf preload module taking over stdout/stdin of kernel.

2022-02-25T20:48:35+00:00

In cb80ddc67152 ("bpf: Convert bpf_preload.ko to use light skeleton.")
BPF preload was switched from user mode process to use in-kernel light
skeleton instead. However, in the kernel context, early in the boot
sequence, the first available FD can start from 0, instead of normally
3 for user mode process. So FDs 0 and 1 are then used for loaded BPF
programs and prevent init process from setting up stdin/stdout/stderr on
FD 0, 1, and 2 as expected.

Before the fix:

ls -lah /proc/1/fd/*

lrwx------1 root root 64 Feb 23 17:20 /proc/1/fd/0 -> /dev/null
lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/1 -> /dev/null
lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/2 -> /dev/console
lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/6 -> /dev/console
lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/7 -> /dev/console

After the fix:

ls -lah /proc/1/fd/*

lrwx------ 1 root root 64 Feb 24 21:23 /proc/1/fd/0 -> /dev/console
lrwx------ 1 root root 64 Feb 24 21:23 /proc/1/fd/1 -> /dev/console
lrwx------ 1 root root 64 Feb 24 21:23 /proc/1/fd/2 -> /dev/console

Fix by closing prog FDs after initialization. struct bpf_prog's
themselves are kept alive through direct kernel references taken with
bpf_link_get_from_fd().

Fixes: cb80ddc67152 ("bpf: Convert bpf_preload.ko to use light skeleton.")
Signed-off-by: Yucong Sun 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20220225185923.2535519-1-fallentree@fb.com

bpf: Convert bpf_preload.ko to use light skeleton.

2022-02-10T22:31:51+00:00

The main change is a move of the single line
  #include "iterators.lskel.h"
from iterators/iterators.c to bpf_preload_kern.c.
Which means that generated light skeleton can be used from user space or
user mode driver like iterators.c or from the kernel module or the kernel itself.
The direct use of light skeleton from the kernel module simplifies the code,
since UMD is no longer necessary. The libbpf.a required user space and UMD. The
CO-RE in the kernel and generated "loader bpf program" used by the light
skeleton are capable to perform complex loading operations traditionally
provided by libbpf. In addition UMD approach was launching UMD process
every time bpffs has to be mounted. With light skeleton in the kernel
the bpf_preload kernel module loads bpf iterators once and pins them
multiple times into different bpffs mounts.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20220209232001.27490-6-alexei.starovoitov@gmail.com

bpf: Update iterators.lskel.h.

2022-02-10T22:31:51+00:00

Light skeleton and skel_internal.h have changed.
Update iterators.lskel.h.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20220209232001.27490-5-alexei.starovoitov@gmail.com

bpf: Drop libbpf, libelf, libz dependency from bpf preload.

2022-02-01T22:56:18+00:00

Drop libbpf, libelf, libz dependency from bpf preload.
This reduces bpf_preload_umd binary size
from 1.7M to 30k unstripped with debug info
and from 300k to 19k stripped.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20220131220528.98088-8-alexei.starovoitov@gmail.com

bpf: Open code obj_get_info_by_fd in bpf preload.

2022-02-01T22:56:18+00:00

Open code obj_get_info_by_fd in bpf preload.
It's the last part of libbpf that preload/iterators were using.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20220131220528.98088-7-alexei.starovoitov@gmail.com

bpf: Convert bpf preload to light skeleton.

2022-02-01T22:56:18+00:00

Convert bpffs preload iterators to light skeleton.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20220131220528.98088-6-alexei.starovoitov@gmail.com

bpf: Remove unnecessary setrlimit from bpf preload.

2022-02-01T22:56:18+00:00

BPF programs and maps are memcg accounted. setrlimit is obsolete.
Remove its use from bpf preload.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20220131220528.98088-5-alexei.starovoitov@gmail.com