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Andrii Nakryiko 25498a1969 libbpf: Always specify expected_attach_type on program load if supported
For some types of BPF programs that utilize expected_attach_type, libbpf won't
set load_attr.expected_attach_type, even if expected_attach_type is known from
section definition. This was done to preserve backwards compatibility with old
kernels that didn't recognize expected_attach_type attribute yet (which was
added in 5e43f899b0 ("bpf: Check attach type at prog load time"). But this
is problematic for some BPF programs that utilize newer features that require
kernel to know specific expected_attach_type (e.g., extended set of return
codes for cgroup_skb/egress programs).

This patch makes libbpf specify expected_attach_type by default, but also
detect support for this field in kernel and not set it during program load.
This allows to have a good metadata for bpf_program
(e.g., bpf_program__get_extected_attach_type()), but still work with old
kernels (for cases where it can work at all).

Additionally, due to expected_attach_type being always set for recognized
program types, bpf_program__attach_cgroup doesn't have to do extra checks to
determine correct attach type, so remove that additional logic.

Also adjust section_names selftest to account for this change.

More detailed discussion can be found in [0].

  [0] https://lore.kernel.org/bpf/20200412003604.GA15986@rdna-mbp.dhcp.thefacebook.com/

Fixes: 5cf1e91456 ("bpf: cgroup inet skb programs can return 0 to 3")
Fixes: 5e43f899b0 ("bpf: Check attach type at prog load time")
Reported-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/20200414182645.1368174-1-andriin@fb.com
2020-04-15 13:22:43 +02:00
Documentation docs: networking: add full DIM API 2020-04-10 18:11:04 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch arm, bpf: Fix offset overflow for BPF_MEM BPF_DW 2020-04-14 21:27:54 +02:00
block SCSI misc on 20200402 2020-04-02 17:03:53 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-04-01 14:47:40 -07:00
drivers net: tun: record RX queue in skb before do_xdp_generic() 2020-04-12 20:58:24 -07:00
fs Merge branch 'akpm' (patches from Andrew) 2020-04-07 14:11:54 -07:00
include net: ipv6: do not consider routes via gateways for anycast address check 2020-04-07 18:26:52 -07:00
init init/Kconfig: clean up ANON_INODES and old IO schedulers options 2020-04-07 10:43:44 -07:00
ipc ipc/shm.c: make compat_ksys_shmctl() static 2020-04-07 10:43:45 -07:00
kernel bpf: remove unneeded conversion to bool in __mark_reg_unknown 2020-04-14 21:40:06 +02:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-04-09 17:39:22 -07:00
mm kasan: unset panic_on_warn before calling panic() 2020-04-07 10:43:44 -07:00
net xsk: Add missing check on user supplied headroom size 2020-04-15 13:07:18 +02:00
samples samples/hw_breakpoint: drop use of kallsyms_lookup_name() 2020-04-07 10:43:44 -07:00
scripts ubsan: split "bounds" checker from other options 2020-04-07 10:43:44 -07:00
security Keyrings fixes 2020-04-04 12:24:47 -07:00
sound SPDX patches for 5.7-rc1. 2020-04-03 13:12:26 -07:00
tools libbpf: Always specify expected_attach_type on program load if supported 2020-04-15 13:22:43 +02:00
usr .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
virt KVM: Pass kvm_init()'s opaque param to additional arch funcs 2020-03-31 10:48:03 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-03-06 21:50:05 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
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.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
.mailmap media updates for v5.7-rc1 2020-03-30 13:42:05 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS docs: networking: convert DIM to RST 2020-04-10 18:10:59 -07:00
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README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.