Start libbpf 1.0 development cycle by adding LIBBPF_1.0.0 section to
libbpf.map file and marking all current symbols as local. As we remove
all the deprecated APIs we'll populate global list before the final 1.0
release.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220518185915.3529475-3-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Add the same negative ABS filter that we use in VERSIONED_SYM_COUNT to
filter out ABS symbols like LIBBPF_0.8.0.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220518185915.3529475-2-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

When build bpf test and install it to another folder, e.g.

  make -j10 install -C tools/testing/selftests/ TARGETS="bpf" \
	SKIP_TARGETS="" INSTALL_PATH=/tmp/kselftests

The ima_setup.sh is missed in target folder, which makes test_ima failed.

Fix it by adding ima_setup.sh to TEST_PROGS_EXTENDED.

Fixes: 34b82d3a ("bpf: Add a selftest for bpf_ima_inode_hash")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220516040020.653291-1-liuhangbin@gmail.com

bpf selftests can no longer be built with CFLAGS=-static with
liburandom_read.so and its dependent target.

Filter out -static for liburandom_read.so and its dependent target.

When building statically, this leaves urandom_read relying on
system-wide shared libraries.
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220514002115.1376033-1-yosryahmed@google.com

Fix sec_name memory leak if user defines target-less SEC("tp").

Fixes: 9af8efc4 ("libbpf: Allow "incomplete" basic tracing SEC() definitions")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220516184547.3204674-1-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Currently, dumping almost all BTFs specified by id requires
using the -B option to pass the base BTF. For kernel module
BTFs the vmlinux BTF sysfs path should work.

This patch simplifies dumping by ID usage by loading
vmlinux BTF from sysfs as base, if base BTF was not specified
and the ID corresponds to a kernel module BTF.
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Link: https://lore.kernel.org/bpf/20220513121743.12411-1-larysa.zaremba@intel.com

Instead of having uninitialized versions of arguments as separate
bpf_arg_types (eg ARG_PTR_TO_UNINIT_MEM as the uninitialized version
of ARG_PTR_TO_MEM), we can instead use MEM_UNINIT as a bpf_type_flag
modifier to denote that the argument is uninitialized.

Doing so cleans up some of the logic in the verifier. We no longer
need to do two checks against an argument type (eg "if
(base_type(arg_type) == ARG_PTR_TO_MEM || base_type(arg_type) ==
ARG_PTR_TO_UNINIT_MEM)"), since uninitialized and initialized
versions of the same argument type will now share the same base type.

In the near future, MEM_UNINIT will be used by dynptr helper functions
as well.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220509224257.3222614-2-joannelkoong@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

usdt_400 test case relies on compiler using the same arg spec for
usdt_400 USDT. This assumption breaks with Clang (Clang generates
different arg specs with varying offsets relative to %rbp), so simplify
this further and hard-code the constant which will guarantee that arg
spec is the same across all 400 inlinings.

Fixes: 630301b0 ("selftests/bpf: Add basic USDT selftests")
Reported-by: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220513173703.89271-1-andrii@kernel.org

Convert a bunch of selftests to using newly added high-level BPF map
APIs.

This change exposed that map_kptr selftests allocated too big buffer,
which is fixed in this patch as well.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220512220713.2617964-2-andrii@kernel.org

Add high-level API wrappers for most common and typical BPF map
operations that works directly on instances of struct bpf_map * (so
you don't have to call bpf_map__fd()) and validate key/value size
expectations.

These helpers require users to specify key (and value, where
appropriate) sizes when performing lookup/update/delete/etc. This forces
user to actually think and validate (for themselves) those. This is
a good thing as user is expected by kernel to implicitly provide correct
key/value buffer sizes and kernel will just read/write necessary amount
of data. If it so happens that user doesn't set up buffers correctly
(which bit people for per-CPU maps especially) kernel either randomly
overwrites stack data or return -EFAULT, depending on user's luck and
circumstances. These high-level APIs are meant to prevent such
unpleasant and hard to debug bugs.

This patch also adds bpf_map_delete_elem_flags() low-level API and
requires passing flags to bpf_map__delete_elem() API for consistency
across all similar APIs, even though currently kernel doesn't expect
any extra flags for BPF_MAP_DELETE_ELEM operation.

List of map operations that get these high-level APIs:

  - bpf_map_lookup_elem;
  - bpf_map_update_elem;
  - bpf_map_delete_elem;
  - bpf_map_lookup_and_delete_elem;
  - bpf_map_get_next_key.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220512220713.2617964-1-andrii@kernel.org

Check that ld_imm64 with src_reg=1 (aka BPF_PSEUDO_FUNC) works
with jit_blinding.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220513011025.13344-2-alexei.starovoitov@gmail.com

The combination of jit blinding and pointers to bpf subprogs causes:
[   36.989548] BUG: unable to handle page fault for address: 0000000100000001
[   36.990342] #PF: supervisor instruction fetch in kernel mode
[   36.990968] #PF: error_code(0x0010) - not-present page
[   36.994859] RIP: 0010:0x100000001
[   36.995209] Code: Unable to access opcode bytes at RIP 0xffffffd7.
[   37.004091] Call Trace:
[   37.004351]  <TASK>
[   37.004576]  ? bpf_loop+0x4d/0x70
[   37.004932]  ? bpf_prog_3899083f75e4c5de_F+0xe3/0x13b

The jit blinding logic didn't recognize that ld_imm64 with an address
of bpf subprogram is a special instruction and proceeded to randomize it.
By itself it wouldn't have been an issue, but jit_subprogs() logic
relies on two step process to JIT all subprogs and then JIT them
again when addresses of all subprogs are known.
Blinding process in the first JIT phase caused second JIT to miss
adjustment of special ld_imm64.

Fix this issue by ignoring special ld_imm64 instructions that don't have
user controlled constants and shouldn't be blinded.

Fixes: 69c087ba ("bpf: Add bpf_for_each_map_elem() helper")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220513011025.13344-1-alexei.starovoitov@gmail.com

The cnt value in the 'cnt >= BPF_MAX_TRAMP_PROGS' check does not
include BPF_TRAMP_MODIFY_RETURN bpf programs, so the number of
the attached BPF_TRAMP_MODIFY_RETURN bpf programs in a trampoline
can exceed BPF_MAX_TRAMP_PROGS.

When this happens, the assignment '*progs++ = aux->prog' in
bpf_trampoline_get_progs() will cause progs array overflow as the
progs field in the bpf_tramp_progs struct can only hold at most
BPF_MAX_TRAMP_PROGS bpf programs.

Fixes: 88fd9e53 ("bpf: Refactor trampoline update code")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Link: https://lore.kernel.org/r/20220430130803.210624-1-ytcoode@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

fexit_stress is attaching maximum allowed amount of fexit programs to
bpf_fentry_test1 kernel function, which is used by a bunch of other
parallel tests, thus pretty frequently interfering with their execution.

Given the test assumes nothing else is attaching to bpf_fentry_test1,
mark it serial.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220511232012.609370-1-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Feng zhou says:

====================

From: Feng Zhou <zhoufeng.zf@bytedance.com>

Trace some functions, such as enqueue_task_fair, need to access the
corresponding cpu, not the current cpu, and bpf_map_lookup_elem percpu map
cannot do it. So add bpf_map_lookup_percpu_elem to accomplish it for
percpu_array_map, percpu_hash_map, lru_percpu_hash_map.

v1->v2: Addressed comments from Alexei Starovoitov.
- add a selftest for bpf_map_lookup_percpu_elem.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

test_progs:
Tests new ebpf helpers bpf_map_lookup_percpu_elem.
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Link: https://lore.kernel.org/r/20220511093854.411-3-zhoufeng.zf@bytedance.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Add new ebpf helpers bpf_map_lookup_percpu_elem.

The implementation method is relatively simple, refer to the implementation
method of map_lookup_elem of percpu map, increase the parameters of cpu, and
obtain it according to the specified cpu.
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Link: https://lore.kernel.org/r/20220511093854.411-2-zhoufeng.zf@bytedance.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Kumar Kartikeya Dwivedi says:

====================

Fix a build time warning, and address comments from Alexei on the merged
version [0].

  [0]: https://lore.kernel.org/bpf/20220424214901.2743946-1-memxor@gmail.com

Changelog:
----------
v1 -> v2
v1: https://lore.kernel.org/bpf/20220510211727.575686-1-memxor@gmail.com

 * Add Fixes tag to patch 1
 * Fix test_progs-noalu32 failure in CI due to different alloc_insn (Alexei)
 * Remove per-CPU struct, use global struct (Alexei)
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Check at runtime how various operations for kptr_ref affect its refcount
and verify against the actual count.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220511194654.765705-5-memxor@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

This uses the newly added SEC("?foo") naming to disable autoload of
programs, and then loads them one by one for the object and verifies
that loading fails and matches the returned error string from verifier.
This is similar to already existing verifier tests but provides coverage
for BPF C.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220511194654.765705-4-memxor@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

In an effort to actually test the refcounting logic at runtime, add a
refcount_t member to prog_test_ref_kfunc and use it in selftests to
verify and test the whole logic more exhaustively.

The kfunc calls for prog_test_member do not require runtime refcounting,
as they are only used for verifier selftests, not during runtime
execution. Hence, their implementation now has a WARN_ON_ONCE as it is
not meant to be reachable code at runtime. It is strictly used in tests
triggering failure cases in the verifier. bpf_kfunc_call_memb_release is
called from map free path, since prog_test_member is embedded in map
value for some verifier tests, so we skip WARN_ON_ONCE for it.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220511194654.765705-3-memxor@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Kernel Test Robot complained about missing static storage class
annotation for bpf_kptr_xchg_proto variable.

sparse: symbol 'bpf_kptr_xchg_proto' was not declared. Should it be static?

This caused by missing extern definition in the header. Add it to
suppress the sparse warning.

Fixes: c0a5a21c ("bpf: Allow storing referenced kptr in map")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220511194654.765705-2-memxor@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

With latest clang, I got the following compilation errors:
  .../prog_tests/test_tunnel.c:291:6: error: variable 'local_ip_map_fd' is used uninitialized
     whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
       if (attach_tc_prog(&tc_hook, -1, set_dst_prog_fd))
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  .../bpf/prog_tests/test_tunnel.c:312:6: note: uninitialized use occurs here
        if (local_ip_map_fd >= 0)
            ^~~~~~~~~~~~~~~
  ...
  .../prog_tests/kprobe_multi_test.c:346:6: error: variable 'err' is used uninitialized
      whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
        if (IS_ERR(map))
            ^~~~~~~~~~~
  .../prog_tests/kprobe_multi_test.c:388:6: note: uninitialized use occurs here
        if (err) {
            ^~~

This patch fixed the above compilation errors.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220511184735.3670214-1-yhs@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Some of the BPF selftests are failing when running with a rather bare
bones configuration based on tools/testing/selftests/bpf/config.
Specifically, we see a bunch of failures due to errno 95:

  > test_attach_api:PASS:fentry_raw_skel_load 0 nsec
  > libbpf: prog 'test_kprobe_manual': failed to attach: Operation not supported
  > test_attach_api:FAIL:bpf_program__attach_kprobe_multi_opts unexpected error: -95
  > 79 /6     kprobe_multi_test/attach_api_syms:FAIL

The cause of these is that CONFIG_FPROBE is missing. With this change we
add this configuration value to the BPF selftests config.
Signed-off-by: Daniel Müller <deso@posteo.net>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220511172249.4082510-1-deso@posteo.netSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Magnus Karlsson says:

====================

This patch set adds busy-poll testing to the xsk selftests. It runs
exactly the same tests as with regular softirq processing, but with
busy-poll enabled. I have also included a number of fixes to the
selftests that have been bugging me for a while or was discovered
while implementing the busy-poll support. In summary these are:

* Fix the error reporting of failed tests. Each failed test used to be
  reported as both failed and passed, messing up things.

* Added a summary test printout at the end of the test suite so that
  users do not have to scroll up and look at the result of both the
  softirq run and the busy_poll run.

* Added a timeout to the tests, so that if a test locks up, we report
  a fail and still get to run all the other tests.

* Made the stats test just look and feel like all the other
  tests. Makes the code simpler and the test reporting more
  consistent. These are the 3 last commits.

* Replaced zero length packets with packets of 64 byte length. This so
  that some of the tests will pass after commit 726e2c59 ("veth:
  Ensure eth header is in skb's linear part").

* Added clean-up of the veth pair when terminating the test run.

* Some smaller clean-ups of unused stuff.

Note, to pass the busy-poll tests commit 8de8b71b ("xsk: Fix
l2fwd for copy mode + busy poll combo") need to be present. It is
present in bpf but not yet in bpf-next.

Thanks: Magnus
====================
Acked-by: Björn Töpel <bjorn@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Convert the stats tests from spinning on the getsockopt to just check
getsockopt once when the Rx thread has received all the packets. The
actual completion of receiving the last packet forms a natural point
in time when the receiver is ready to call the getsockopt to check the
stats. In the previous version , we just span on the getsockopt until
we received the right answer. This could be forever or just getting
the "correct" answer by shear luck.

The pacing_on variable can now be dropped since all test can now
handle pacing properly.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-10-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Make the stats tests look and feel just like normal tests instead of
bunched under the umbrella of TEST_STATS. This means we will always
run each of them even if one fails. Also gets rid of some special case
code.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-9-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce validation functions that can be optionally called by the Rx
and Tx threads. These are then used to replace the Rx and Tx stats
dispatchers. This so that we in the next commit can make the stats
tests proper normal tests and not be some special case, as today.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-8-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Remove the veth pair when the tests are aborted by pressing
ctrl-c. Currently in this situation, the veth pair is left on the
system polluting the netdev space.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-7-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Add a timeout to the tests so that if all packets have not been
received within 3 seconds, fail the ongoing test. Hinders a test from
dead-locking if there is something wrong.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-6-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Fix the reporting of failed tests as it was broken in several
ways. First, a failed test was reported as both failed and passed
messing up the count. Second, tests were not aborted after a failure
and could generate more "failures" messing up the count even
more. Third, the failure reporting from the application to the shell
script was wrong. It always reported pass. And finally, the handling
of the failures in the launch script was not correct.

Correct all this by propagating the failure up through the function
calls to a calling function that can abort the test. A receiver or
sender thread will mark the new variable in the test spec called fail,
if a test has failed. This is then picked up by the main thread when
everyone else has exited and this is then marked and propagated up to
the calling script.

Also add a summary function in the calling script so that a user
does not have to go through the sub tests to see if something has
failed.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-5-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Execute all xsk selftests for busy-poll mode too. Currently they were
only run for the standard interrupt driven softirq mode. Replace the
unused option queue-id with the new option busy-poll.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-4-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Do not try to send packets of zero length since they are dropped by
veth after commit 726e2c59 ("veth: Ensure eth header is in skb's
linear part"). Replace these two packets with packets of length 60 so
that they are not dropped.

Also clean up the confusing naming. MIN_PKT_SIZE was really
MIN_ETH_PKT_SIZE and PKT_SIZE was both MIN_ETH_SIZE and the default
packet size called just PKT_SIZE. Make it consistent by using the
right define in the right place.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-3-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Remove the spec-file that is not used any longer from the shell
scripts. Also remove an unused option.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-2-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Adding bpf_program__set_insns that allows to set new instructions
for a BPF program.

This is a very advanced libbpf API and users need to know what
they are doing. This should be used from prog_prepare_load_fn
callback only.

We can have changed instructions after calling prog_prepare_load_fn
callback, reloading them.

One of the users of this new API will be perf's internal BPF prologue
generation.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510074659.2557731-2-jolsa@kernel.org

Drop unused iteration variable, move overflow prevention check into the
for loop.

Fixes: 0087a681 ("libbpf: Automatically fix up BPF_MAP_TYPE_RINGBUF size, if necessary")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220510185159.754299-1-andrii@kernel.org

Kui-Feng Lee says:

====================

Allow users to attach a 64-bits cookie to a bpf_link of fentry, fexit,
or fmod_ret.

This patchset includes several major changes.

 - Define struct bpf_tramp_links to replace bpf_tramp_prog.
   struct bpf_tramp_links collects bpf_links of a trampoline

 - Generate a trampoline to call bpf_progs of given bpf_links.

 - Trampolines always set/reset bpf_run_ctx before/after
   calling/leaving a tracing program.

 - Attach a cookie to a bpf_link of fentry/fexit/fmod_ret/lsm.  The
   value will be available when running the associated bpf_prog.

Th major differences from v6:

 - bpf_link_create() can create links of BPF_LSM_MAC attach type.

 - Add a test for lsm.

 - Add function proto of bpf_get_attach_cookie() for lsm.

 - Check BPF_LSM_MAC in bpf_prog_has_trampoline().

 - Adapt to the changes of LINK_CREATE made by Andrii.

The major differences from v7:

 - Change stack_size instead of pushing/popping run_ctx.

 - Move cookie to bpf_tramp_link from bpf_tracing_link..

v1: https://lore.kernel.org/all/20220126214809.3868787-1-kuifeng@fb.com/
v2: https://lore.kernel.org/bpf/20220316004231.1103318-1-kuifeng@fb.com/
v3: https://lore.kernel.org/bpf/20220407192552.2343076-1-kuifeng@fb.com/
v4: https://lore.kernel.org/bpf/20220411173429.4139609-1-kuifeng@fb.com/
v5: https://lore.kernel.org/bpf/20220412165555.4146407-1-kuifeng@fb.com/
v6: https://lore.kernel.org/bpf/20220416042940.656344-1-kuifeng@fb.com/
v7: https://lore.kernel.org/bpf/20220508032117.2783209-1-kuifeng@fb.com/
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

Make sure BPF cookies are correct for fentry/fexit/fmod_ret/lsm.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-6-kuifeng@fb.com

Add a cookie field to the attributes of bpf_link_create().
Add bpf_program__attach_trace_opts() to attach a cookie to a link.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-5-kuifeng@fb.com

Pass a cookie along with BPF_LINK_CREATE requests.

Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie.
The cookie of a bpf_tracing_link is available by calling
bpf_get_attach_cookie when running the BPF program of the attached
link.

The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com