selftests/bpf: Add test for abnormal cnt during multi-kprobe attachment

If an abnormally huge cnt is used for multi-kprobes attachment, the
following warning will be reported:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 392 at mm/util.c:632 kvmalloc_node+0xd9/0xe0
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 392 Comm: test_progs Tainted: G ...... 6.7.0-rc3+ #32
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
......
RIP: 0010:kvmalloc_node+0xd9/0xe0
? __warn+0x89/0x150
? kvmalloc_node+0xd9/0xe0
bpf_kprobe_multi_link_attach+0x87/0x670
__sys_bpf+0x2a28/0x2bc0
__x64_sys_bpf+0x1a/0x30
do_syscall_64+0x36/0xb0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
RIP: 0033:0x7fbe067f0e0d
......
</TASK>
---[ end trace 0000000000000000 ]---

So add a test to ensure the warning is fixed.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231215100708.2265609-6-houtao@huaweicloud.com

selftests/bpf: Don't use libbpf_get_error() in kprobe_multi_test

Since libbpf v1.0, libbpf doesn't return error code embedded into the
pointer iteself, libbpf_get_error() is deprecated and it is basically
the same as using -errno directly.

So replace the invocations of libbpf_get_error() by -errno in
kprobe_multi_test. For libbpf_get_error() in test_attach_api_fails(),
saving -errno before invoking ASSERT_xx() macros just in case that
errno is overwritten by these macros. However, the invocation of
libbpf_get_error() in get_syms() should be kept intact, because
hashmap__new() still returns a pointer with embedded error code.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231215100708.2265609-5-houtao@huaweicloud.com

selftests/bpf: Fix kprobe_multi_test/attach_override test

We need to deny the attach_override test for arm64, denying the
whole kprobe_multi_test suite. Also making attach_override static.

Fixes: 7182e56411b9 ("selftests/bpf: Add kprobe_multi override test")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230913114711.499829-1-jolsa@kernel.org

selftests/bpf: Add kprobe_multi override test

Adding test that tries to attach program with bpf_override_return
helper to function not within error injection list.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230907200652.926951-2-jolsa@kernel.org

selftests/bpf: Move get_time_ns to testing_helpers.h

We'd like to have single copy of get_time_ns used b bench and test_progs,
but we can't just include bench.h, because of conflicting 'struct env'
objects.

Moving get_time_ns to testing_helpers.h which is being included by both
bench and test_progs objects.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-19-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Reset err when symbol name already exist in kprobe_multi_test

When trying to add a name to the hashmap, an error code of EEXIST is
returned and we continue as names are possibly duplicated in the sys
file.

If the last name in the file is a duplicate, we will continue to the
next iteration of the while loop, and exit the loop with a value of err
set to EEXIST and enter the error label with err set, which causes the
test to fail when it should not.

This change reset err to 0 before continue-ing into the next iteration,
this way, if there is no more data to read from the file we iterate
through, err will be set to 0.

Behaviour prior to this change:
```
test_kprobe_multi_bench_attach:FAIL:get_syms unexpected error: -17
(errno 2)

All error logs:
test_kprobe_multi_bench_attach:FAIL:get_syms unexpected error: -17
(errno 2)
Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED
```

After this change:
```
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
```

Signed-off-by: Manu Bretelle <chantr4@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230408022919.54601-1-chantr4@gmail.com

selftests/bpf: use canonical ftrace path

The canonical location for the tracefs filesystem is at
/sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

Before 4.1, all ftrace tracing control files were within the debugfs
file system, which is typically located at /sys/kernel/debug/tracing.
For backward compatibility, when mounting the debugfs file system,
the tracefs file system will be automatically mounted at:

/sys/kernel/debug/tracing

Many tests in the bpf selftest code still refer to this older debugfs
path, so let's update them to avoid confusion.

Signed-off-by: Ross Zwisler <zwisler@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230313205628.1058720-3-zwisler@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Add serial_test_kprobe_multi_bench_attach_kernel/module tests

Add bench test for module portion of the symbols as well.

# ./test_progs -v -t kprobe_multi_bench_attach_module
bpf_testmod.ko is already unloaded.
Loading bpf_testmod.ko...
Successfully loaded bpf_testmod.ko.
test_kprobe_multi_bench_attach:PASS:get_syms 0 nsec
test_kprobe_multi_bench_attach:PASS:kprobe_multi_empty__open_and_load 0 nsec
test_kprobe_multi_bench_attach:PASS:bpf_program__attach_kprobe_multi_opts 0 nsec
test_kprobe_multi_bench_attach: found 26620 functions
test_kprobe_multi_bench_attach: attached in 0.182s
test_kprobe_multi_bench_attach: detached in 0.082s
#96 kprobe_multi_bench_attach_module:OK
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
Successfully unloaded bpf_testmod.ko.

It's useful for testing kprobe multi link modules resolving.

Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230116101009.23694-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

libbpf: Hashmap interface update to allow both long and void* keys/values

An update for libbpf's hashmap interface from void* -> void* to a
polymorphic one, allowing both long and void* keys and values.

This simplifies many use cases in libbpf as hashmaps there are mostly
integer to integer.

Perf copies hashmap implementation from libbpf and has to be
updated as well.

Changes to libbpf, selftests/bpf and perf are packed as a single
commit to avoid compilation issues with any future bisect.

Polymorphic interface is acheived by hiding hashmap interface
functions behind auxiliary macros that take care of necessary
type casts, for example:

#define hashmap_cast_ptr(p) \
({ \
_Static_assert((p) == NULL || sizeof(*(p)) == sizeof(long),\
#p " pointee should be a long-sized integer or a pointer"); \
(long *)(p); \
})

bool hashmap_find(const struct hashmap *map, long key, long *value);

#define hashmap__find(map, key, value) \
hashmap_find((map), (long)(key), hashmap_cast_ptr(value))

- hashmap__find macro casts key and value parameters to long
and long* respectively
- hashmap_cast_ptr ensures that value pointer points to a memory
of appropriate size.

This hack was suggested by Andrii Nakryiko in [1].
This is a follow up for [2].

[1] https://lore.kernel.org/bpf/CAEf4BzZ8KFneEJxFAaNCCFPGqp20hSpS2aCj76uRk3-qZUH5xg@mail.gmail.com/
[2] https://lore.kernel.org/bpf/af1facf9-7bc8-8a3d-0db4-7b3f333589a2@meta.com/T/#m65b28f1d6d969fcd318b556db6a3ad499a42607d

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221109142611.879983-2-eddyz87@gmail.com

selftest/bpf: Fix memory leak in kprobe_multi_test

The get_syms() function in kprobe_multi_test.c does not free the string
memory allocated by sscanf correctly. Fix it.

Fixes: 5b6c7e5c4434 ("selftests/bpf: Add attach bench test")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20221011120108.782373-5-xukuohai@huaweicloud.com

selftests/bpf: Make test_bench_attach serial

Alexei hit another rcu warnings because of this test.

Making test_bench_attach serial so it does not disrupts
other tests during parallel tests run.

While this change is not the fix, it should be less likely
to hit it with this test being executed serially.

Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221116100228.2064612-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Filter out default_idle from kprobe_multi bench

Alexei hit following rcu warning when running prog_test -j.

[ 128.049567] WARNING: suspicious RCU usage
[ 128.049569] 6.1.0-rc2 #912 Tainted: G O
...
[ 128.050944] kprobe_multi_link_handler+0x6c/0x1d0
[ 128.050947] ? kprobe_multi_link_handler+0x42/0x1d0
[ 128.050950] ? __cpuidle_text_start+0x8/0x8
[ 128.050952] ? __cpuidle_text_start+0x8/0x8
[ 128.050958] fprobe_handler.part.1+0xac/0x150
[ 128.050964] 0xffffffffa02130c8
[ 128.050991] ? default_idle+0x5/0x20
[ 128.050998] default_idle+0x5/0x20

It's caused by bench test attaching kprobe_multi link to default_idle
function, which is not executed in rcu safe context so the kprobe
handler on top of it will trigger the rcu warning.

Filtering out default_idle function from the bench test.

Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221116100228.2064612-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Do not attach kprobe_multi bench to bpf_dispatcher_xdp_func

Alexei reported crash by running test_progs -j on system
with 32 cpus.

It turned out the kprobe_multi bench test that attaches all
ftrace-able functions will race with bpf_dispatcher_update,
that calls bpf_arch_text_poke on bpf_dispatcher_xdp_func,
which is ftrace-able function.

Ftrace is not aware of this update so this will cause
ftrace_bug with:

WARNING: CPU: 6 PID: 1985 at
arch/x86/kernel/ftrace.c:94 ftrace_verify_code+0x27/0x50
...
ftrace_replace_code+0xa3/0x170
ftrace_modify_all_code+0xbd/0x150
ftrace_startup_enable+0x3f/0x50
ftrace_startup+0x98/0xf0
register_ftrace_function+0x20/0x60
register_fprobe_ips+0xbb/0xd0
bpf_kprobe_multi_link_attach+0x179/0x430
__sys_bpf+0x18a1/0x2440
...
------------[ ftrace bug ]------------
ftrace failed to modify
[<ffffffff818d9380>] bpf_dispatcher_xdp_func+0x0/0x10
actual: ffffffe9:7b:ffffff9c:77:1e
Setting ftrace call site to call ftrace function

It looks like we need some way to hide some functions
from ftrace, but meanwhile we workaround this by skipping
bpf_dispatcher_xdp_func from kprobe_multi bench test.

Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220714082316.479181-1-jolsa@kernel.org

selftests/bpf: Fix few more compiler warnings

When compiling with -O2, GCC detects few problems with selftests/bpf, so
fix all of them. Two are real issues (uninitialized err and nums
out-of-bounds access), but two other uninitialized variables warnings
are due to GCC not being able to prove that variables are indeed
initialized under conditions under which they are used.

Fix all 4 cases, though.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20220705224818.4026623-3-andrii@kernel.org

selftest/bpf: Fix kprobe_multi bench test

With [1] the available_filter_functions file contains records
starting with __ftrace_invalid_address___ and marking disabled
entries.

We need to filter them out for the bench test to pass only
resolvable symbols to kernel.

[1] commit b39181f7c690 ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function")

Fixes: b39181f7c690 ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220615112118.497303-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: fix a few clang compilation errors

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.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Add attach bench test

Adding test that reads all functions from ftrace available_filter_functions
file and attach them all through kprobe_multi API.

It also prints stats info with -v option, like on my setup:

test_bench_attach: found 48712 functions
test_bench_attach: attached in 1.069s
test_bench_attach: detached in 0.373s

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Use target-less SEC() definitions in various tests

Add new or modify existing SEC() definitions to be target-less and
validate that libbpf handles such program definitions correctly.

For kprobe/kretprobe we also add explicit test that generic
bpf_program__attach() works in cases when kprobe definition contains
proper target. It wasn't previously tested as selftests code always
explicitly specified the target regardless.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220428185349.3799599-4-andrii@kernel.org

selftests/bpf: Add attach test for bpf_program__attach_kprobe_multi_opts

Adding tests for bpf_program__attach_kprobe_multi_opts function,
that test attach with pattern, symbols and addrs.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-13-jolsa@kernel.org

selftests/bpf: Add kprobe_multi attach test

Adding kprobe_multi attach test that uses new fprobe interface to
attach kprobe program to multiple functions.

The test is attaching programs to bpf_fentry_test* functions and
uses single trampoline program bpf_prog_test_run to trigger
bpf_fentry_test* functions.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-11-jolsa@kernel.org