linux.git/kernel/bpf/preload, branch v6.6.131

bpf/preload: Don't select USERMODE_DRIVER

2025-08-15T10:08:51+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: make preloaded map iterators to display map elements count

2023-07-06T19:42:25+00:00

Add another column to the /sys/fs/bpf/maps.debug iterator to display
cur_entries, the current number of entries in the map as is returned
by the bpf_map_sum_elem_count kfunc. Also fix formatting.

Example:

    # cat /sys/fs/bpf/maps.debug
      id name             max_entries  cur_entries
       2 iterator.rodata            1            0
     125 cilium_auth_map       524288          666
     126 cilium_runtime_          256            0
     127 cilium_signals            32            0
     128 cilium_node_map        16384         1344
     129 cilium_events             32            0
     ...

Signed-off-by: Anton Protopopov 
Link: https://lore.kernel.org/r/20230706133932.45883-5-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov

bpf: Replace deprecated -target with --target= for Clang

2023-06-29T13:46:17+00:00

The -target option has been deprecated since clang 3.4 in 2013. Therefore, use
the preferred --target=bpf form instead. This also matches how we use --target=
in scripts/Makefile.clang.

Signed-off-by: Fangrui Song 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Acked-by: Quentin Monnet 
Link: https://github.com/llvm/llvm-project/commit/274b6f0c87a6a1798de0a68135afc7f95def6277
Link: https://lore.kernel.org/bpf/20230624001856.1903733-1-maskray@google.com

bpf: Replace all non-returning strlcpy with strscpy

2023-05-31T11:04:20+00:00

strlcpy() reads the entire source buffer first. This read may exceed the
destination size limit. This is both inefficient and can lead to linear
read overflows if a source string is not NUL-terminated [1]. This is not
the case here, however, in an effort to remove strlcpy() completely [2],
lets replace strlcpy() here with strscpy(). No return values were used,
so a direct replacement is safe.

  [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
  [2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/bpf/20230530155659.309657-1-azeemshaikh38@gmail.com

bpf: iterators: Split iterators.lskel.h into little- and big- endian versions

2023-01-28T20:45:15+00:00

iterators.lskel.h is little-endian, therefore bpf iterator is currently
broken on big-endian systems. Introduce a big-endian version and add
instructions regarding its generation. Unfortunately bpftool's
cross-endianness capabilities are limited to BTF right now, so the
procedure requires access to a big-endian machine or a configured
emulator.

Signed-off-by: Ilya Leoshkevich 
Link: https://lore.kernel.org/r/20230128000650.1516334-25-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov

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