Andrii Nakryiko says:

====================
bpf-next 2021-07-30

We've added 64 non-merge commits during the last 15 day(s) which contain
a total of 83 files changed, 5027 insertions(+), 1808 deletions(-).

The main changes are:

1) BTF-guided binary data dumping libbpf API, from Alan.

2) Internal factoring out of libbpf CO-RE relocation logic, from Alexei.

3) Ambient BPF run context and cgroup storage cleanup, from Andrii.

4) Few small API additions for libbpf 1.0 effort, from Evgeniy and Hengqi.

5) bpf_program__attach_kprobe_opts() fixes in libbpf, from Jiri.

6) bpf_{get,set}sockopt() support in BPF iterators, from Martin.

7) BPF map pinning improvements in libbpf, from Martynas.

8) Improved module BTF support in libbpf and bpftool, from Quentin.

9) Bpftool cleanups and documentation improvements, from Quentin.

10) Libbpf improvements for supporting CO-RE on old kernels, from Shuyi.

11) Increased maximum cgroup storage size, from Stanislav.

12) Small fixes and improvements to BPF tests and samples, from various folks.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (64 commits)
  tools: bpftool: Complete metrics list in "bpftool prog profile" doc
  tools: bpftool: Document and add bash completion for -L, -B options
  selftests/bpf: Update bpftool's consistency script for checking options
  tools: bpftool: Update and synchronise option list in doc and help msg
  tools: bpftool: Complete and synchronise attach or map types
  selftests/bpf: Check consistency between bpftool source, doc, completion
  tools: bpftool: Slightly ease bash completion updates
  unix_bpf: Fix a potential deadlock in unix_dgram_bpf_recvmsg()
  libbpf: Add btf__load_vmlinux_btf/btf__load_module_btf
  tools: bpftool: Support dumping split BTF by id
  libbpf: Add split BTF support for btf__load_from_kernel_by_id()
  tools: Replace btf__get_from_id() with btf__load_from_kernel_by_id()
  tools: Free BTF objects at various locations
  libbpf: Rename btf__get_from_id() as btf__load_from_kernel_by_id()
  libbpf: Rename btf__load() as btf__load_into_kernel()
  libbpf: Return non-null error on failures in libbpf_find_prog_btf_id()
  bpf: Emit better log message if bpf_iter ctx arg btf_id == 0
  tools/resolve_btfids: Emit warnings and patch zero id for missing symbols
  bpf: Increase supported cgroup storage value size
  libbpf: Fix race when pinning maps in parallel
  ...
====================

Link: https://lore.kernel.org/r/20210730225606.1897330-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Profiling programs with bpftool was extended some time ago to support
two new metrics, namely itlb_misses and dtlb_misses (misses for the
instruction/data translation lookaside buffer). Update the manual page
and bash completion accordingly.

Fixes: 450d060e8f75 ("bpftool: Add {i,d}tlb_misses support for bpftool profile")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-8-quentin@isovalent.com

The -L|--use-loader option for using loader programs when loading, or
when generating a skeleton, did not have any documentation or bash
completion. Same thing goes for -B|--base-btf, used to pass a path to a
base BTF object for split BTF such as BTF for kernel modules.

This patch documents and adds bash completion for those options.

Fixes: 75fa1777694c ("tools/bpftool: Add bpftool support for split BTF")
Fixes: d510296d331a ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-7-quentin@isovalent.com

All bpftool commands support the options for JSON output and debug from
libbpf. In addition, some commands support additional options
corresponding to specific use cases.

The list of options described in the man pages for the different
commands are not always accurate. The messages for interactive help are
mostly limited to HELP_SPEC_OPTIONS, and are even less representative of
the actual set of options supported for the commands.

Let's update the lists:

- HELP_SPEC_OPTIONS is modified to contain the "default" options (JSON
  and debug), and to be extensible (no ending curly bracket).
- All commands use HELP_SPEC_OPTIONS in their help message, and then
  complete the list with their specific options.
- The lists of options in the man pages are updated.
- The formatting of the list for bpftool.rst is adjusted to match
  formatting for the other man pages. This is for consistency, and also
  because it will be helpful in a future patch to automatically check
  that the files are synchronised.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-5-quentin@isovalent.com

Update bpftool's list of attach type names to tell it about the latest
attach types, or the "ringbuf" map. Also update the documentation, help
messages, and bash completion when relevant.

These missing items were reported by the newly added Python script used
to help maintain consistency in bpftool.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-4-quentin@isovalent.com

Bash completion for bpftool gets two minor improvements in this patch.

Move the detection of attach types for "bpftool cgroup attach" outside
of the "case/esac" bloc, where we cannot reuse our variable holding the
list of supported attach types as a pattern list. After the change, we
have only one list of cgroup attach types to update when new types are
added, instead of the former two lists.

Also rename the variables holding lists of names for program types, map
types, and attach types, to make them more unique. This can make it
slightly easier to point people to the relevant variables to update, but
the main objective here is to help run a script to check that bash
completion is up-to-date with bpftool's source code.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-2-quentin@isovalent.com

Split BTF objects are typically BTF objects for kernel modules, which
are incrementally built on top of kernel BTF instead of redefining all
kernel symbols they need. We can use bpftool with its -B command-line
option to dump split BTF objects. It works well when the handle provided
for the BTF object to dump is a "path" to the BTF object, typically
under /sys/kernel/btf, because bpftool internally calls
btf__parse_split() which can take a "base_btf" pointer and resolve the
BTF reconstruction (although in that case, the "-B" option is
unnecessary because bpftool performs autodetection).

However, it did not work so far when passing the BTF object through its
id, because bpftool would call btf__get_from_id() which did not provide
a way to pass a "base_btf" pointer.

In other words, the following works:

    # bpftool btf dump file /sys/kernel/btf/i2c_smbus -B /sys/kernel/btf/vmlinux

But this was not possible:

    # bpftool btf dump id 6 -B /sys/kernel/btf/vmlinux

The libbpf API has recently changed, and btf__get_from_id() has been
deprecated in favour of btf__load_from_kernel_by_id() and its version
with support for split BTF, btf__load_from_kernel_by_id_split(). Let's
update bpftool to make it able to dump the BTF object in the second case
as well.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-9-quentin@isovalent.com

Replace the calls to function btf__get_from_id(), which we plan to
deprecate before the library reaches v1.0, with calls to
btf__load_from_kernel_by_id() in tools/ (bpftool, perf, selftests).
Update the surrounding code accordingly (instead of passing a pointer to
the btf struct, get it as a return value from the function).

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-6-quentin@isovalent.com

Make sure to call btf__free() (and not simply free(), which does not
free all pointers stored in the struct) on pointers to struct btf
objects retrieved at various locations.

These were found while updating the calls to btf__get_from_id().

Fixes: 999d82cbc044 ("tools/bpf: enhance test_btf file testing to test func info")
Fixes: 254471e57a86 ("tools/bpf: bpftool: add support for func types")
Fixes: 7b612e291a5a ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs")
Fixes: d56354dc4909 ("perf tools: Save bpf_prog_info and BTF of new BPF programs")
Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command")
Fixes: fa853c4b839e ("perf stat: Enable counting events for BPF programs")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210729162028.29512-5-quentin@isovalent.com

Kernel functions referenced by .BTF_ids may be changed from global to static
and get inlined or get renamed/removed, and thus disappears from BTF.
This causes kernel build failure when resolve_btfids do id patch for symbols
in .BTF_ids in vmlinux. Update resolve_btfids to emit warning messages and
patch zero id for missing symbols instead of aborting kernel build process.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210727132532.2473636-2-hengqi.chen@gmail.com