linux/kernel/bpf/preload, branch v6.4

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

2023-01-28T20:45:15Z

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

2022-07-15T19:01:30Z

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

2022-03-08T06:19:32Z

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.

2022-02-25T20:48:35Z

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.

2022-02-10T22:31:51Z

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.

2022-02-10T22:31:51Z

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.

2022-02-01T22:56:18Z

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.

2022-02-01T22:56:18Z

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.

2022-02-01T22:56:18Z

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.

2022-02-01T22:56:18Z

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