Add BPF-side implementation of libbpf-provided USDT support. This
consists of single header library, usdt.bpf.h, which is meant to be used
from user's BPF-side source code. This header is added to the list of
installed libbpf header, along bpf_helpers.h and others.

BPF-side implementation consists of two BPF maps:
  - spec map, which contains "a USDT spec" which encodes information
    necessary to be able to fetch USDT arguments and other information
    (argument count, user-provided cookie value, etc) at runtime;
  - IP-to-spec-ID map, which is only used on kernels that don't support
    BPF cookie feature. It allows to lookup spec ID based on the place
    in user application that triggers USDT program.

These maps have default sizes, 256 and 1024, which are chosen
conservatively to not waste a lot of space, but handling a lot of common
cases. But there could be cases when user application needs to either
trace a lot of different USDTs, or USDTs are heavily inlined and their
arguments are located in a lot of differing locations. For such cases it
might be necessary to size those maps up, which libbpf allows to do by
overriding BPF_USDT_MAX_SPEC_CNT and BPF_USDT_MAX_IP_CNT macros.

It is an important aspect to keep in mind. Single USDT (user-space
equivalent of kernel tracepoint) can have multiple USDT "call sites".
That is, single logical USDT is triggered from multiple places in user
application. This can happen due to function inlining. Each such inlined
instance of USDT invocation can have its own unique USDT argument
specification (instructions about the location of the value of each of
USDT arguments). So while USDT looks very similar to usual uprobe or
kernel tracepoint, under the hood it's actually a collection of uprobes,
each potentially needing different spec to know how to fetch arguments.

User-visible API consists of three helper functions:
  - bpf_usdt_arg_cnt(), which returns number of arguments of current USDT;
  - bpf_usdt_arg(), which reads value of specified USDT argument (by
    it's zero-indexed position) and returns it as 64-bit value;
  - bpf_usdt_cookie(), which functions like BPF cookie for USDT
    programs; this is necessary as libbpf doesn't allow specifying actual
    BPF cookie and utilizes it internally for USDT support implementation.

Each bpf_usdt_xxx() APIs expect struct pt_regs * context, passed into
BPF program. On kernels that don't support BPF cookie it is used to
fetch absolute IP address of the underlying uprobe.

usdt.bpf.h also provides BPF_USDT() macro, which functions like
BPF_PROG() and BPF_KPROBE() and allows much more user-friendly way to
get access to USDT arguments, if USDT definition is static and known to
the user. It is expected that majority of use cases won't have to use
bpf_usdt_arg_cnt() and bpf_usdt_arg() directly and BPF_USDT() will cover
all their needs.

Last, usdt.bpf.h is utilizing BPF CO-RE for one single purpose: to
detect kernel support for BPF cookie. If BPF CO-RE dependency is
undesirable, user application can redefine BPF_USDT_HAS_BPF_COOKIE to
either a boolean constant (or equivalently zero and non-zero), or even
point it to its own .rodata variable that can be specified from user's
application user-space code. It is important that
BPF_USDT_HAS_BPF_COOKIE is known to BPF verifier as static value (thus
.rodata and not just .data), as otherwise BPF code will still contain
bpf_get_attach_cookie() BPF helper call and will fail validation at
runtime, if not dead-code eliminated.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20220404234202.331384-2-andrii@kernel.org

attach_probe selftest fails on Debian-based distros with `failed to
resolve full path for 'libc.so.6'`. The reason is that these distros
embraced multiarch to the point where even for the "main" architecture
they store libc in /lib/<triple>.

This is configured in /etc/ld.so.conf and in theory it's possible to
replicate the loader's parsing and processing logic in libbpf, however
a much simpler solution is to just enumerate the known library paths.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220404225020.51029-1-iii@linux.ibm.com

Since core relos is an optional part of the .BTF.ext ELF section, we should
skip parsing it instead of returning -EINVAL if header size is less than
offsetofend(struct btf_ext_header, core_relo_len).

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220404005320.1723055-1-ytcoode@gmail.com

Now that u[ret]probes can use name-based specification, it makes
sense to add support for auto-attach based on SEC() definition.
The format proposed is

        SEC("u[ret]probe/binary:[raw_offset|[function_name[+offset]]")

For example, to trace malloc() in libc:

        SEC("uprobe/libc.so.6:malloc")

...or to trace function foo2 in /usr/bin/foo:

        SEC("uprobe//usr/bin/foo:foo2")

Auto-attach is done for all tasks (pid -1).  prog can be an absolute
path or simply a program/library name; in the latter case, we use
PATH/LD_LIBRARY_PATH to resolve the full path, falling back to
standard locations (/usr/bin:/usr/sbin or /usr/lib64:/usr/lib) if
the file is not found via environment-variable specified locations.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648654000-21758-4-git-send-email-alan.maguire@oracle.com

kprobe attach is name-based, using lookups of kallsyms to translate
a function name to an address.  Currently uprobe attach is done
via an offset value as described in [1].  Extend uprobe opts
for attach to include a function name which can then be converted
into a uprobe-friendly offset.  The calcualation is done in
several steps:

1. First, determine the symbol address using libelf; this gives us
   the offset as reported by objdump
2. If the function is a shared library function - and the binary
   provided is a shared library - no further work is required;
   the address found is the required address
3. Finally, if the function is local, subtract the base address
   associated with the object, retrieved from ELF program headers.

The resultant value is then added to the func_offset value passed
in to specify the uprobe attach address.  So specifying a func_offset
of 0 along with a function name "printf" will attach to printf entry.

The modes of operation supported are then

1. to attach to a local function in a binary; function "foo1" in
   "/usr/bin/foo"
2. to attach to a shared library function in a shared library -
   function "malloc" in libc.

[1] https://www.kernel.org/doc/html/latest/trace/uprobetracer.html



Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648654000-21758-3-git-send-email-alan.maguire@oracle.com

bpf_program__attach_uprobe_opts() requires a binary_path argument
specifying binary to instrument.  Supporting simply specifying
"libc.so.6" or "foo" should be possible too.

Library search checks LD_LIBRARY_PATH, then /usr/lib64, /usr/lib.
This allows users to run BPF programs prefixed with
LD_LIBRARY_PATH=/path2/lib while still searching standard locations.
Similarly for non .so files, we check PATH and /usr/bin, /usr/sbin.

Path determination will be useful for auto-attach of BPF uprobe programs
using SEC() definition.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648654000-21758-2-git-send-email-alan.maguire@oracle.com

This patch corrects typos in error messages. I should be "evlist", not
"evsel" as the function that fails is perf_evlist__open().

Fixes: 3ce311af ("libperf: Move to tools/lib/perf")
Fixes: a7f3713f ("libperf tests: Add test_stat_multiplexing test")
Signed-off-by: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20220325043829.224045-2-nakamura.shun@fujitsu.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

pin_fd is dup-ed and assigned in bpf_map__reuse_fd. Close it
in bpf_object__reuse_map after reuse.

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220319030533.3132250-1-hengqi.chen@gmail.com

If BPF object doesn't have an BTF info, don't attempt to search for BTF
types describing BPF map key or value layout.

Fixes: 262cfb74 ("libbpf: Init btf_{key,value}_type_id on internal map open")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220320001911.3640917-1-andrii@kernel.org

In symmetry with bpf_object__open_skeleton(),
bpf_object__open_subskeleton() performs the actual walking and linking
of maps, progs, and globals described by bpf_*_skeleton objects.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/6942a46fbe20e7ebf970affcca307ba616985b15.1647473511.git.delyank@fb.com

For internal and user maps, look up the key and value btf
types on open() and not load(), so that `bpf_map_btf_value_type_id`
is usable in `bpftool gen`.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/78dbe4e457b4a05e098fc6c8f50014b680c86e4e.1647473511.git.delyank@fb.com

Currently, libbpf considers a single routine in .text to be a program. This
is particularly confusing when it comes to library objects - a single routine
meant to be used as an extern will instead be considered a bpf_program.

This patch hides this compatibility behavior behind the pre-existing
SEC_NAME strict mode flag.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/018de8d0d67c04bf436055270d35d394ba393505.1647473511.git.delyank@fb.com

Adding bpf_program__attach_kprobe_multi_opts function for attaching
kprobe program to multiple functions.

  struct bpf_link *
  bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
                                        const char *pattern,
                                        const struct bpf_kprobe_multi_opts *opts);

User can specify functions to attach with 'pattern' argument that
allows wildcards (*?' supported) or provide symbols or addresses
directly through opts argument. These 3 options are mutually
exclusive.

When using symbols or addresses, user can also provide cookie value
for each symbol/address that can be retrieved later in bpf program
with bpf_get_attach_cookie helper.

  struct bpf_kprobe_multi_opts {
          size_t sz;
          const char **syms;
          const unsigned long *addrs;
          const __u64 *cookies;
          size_t cnt;
          bool retprobe;
          size_t :0;
  };

Symbols, addresses and cookies are provided through opts object
(syms/addrs/cookies) as array pointers with specified count (cnt).

Each cookie value is paired with provided function address or symbol
with the same array index.

The program can be also attached as return probe if 'retprobe' is set.

For quick usage with NULL opts argument, like:

  bpf_program__attach_kprobe_multi_opts(prog, "ksys_*", NULL)

the 'prog' will be attached as kprobe to 'ksys_*' functions.

Also adding new program sections for automatic attachment:

  kprobe.multi/<symbol_pattern>
  kretprobe.multi/<symbol_pattern>

The symbol_pattern is used as 'pattern' argument in
bpf_program__attach_kprobe_multi_opts function.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-10-jolsa@kernel.org

Adding new kprobe_multi struct to bpf_link_create_opts object
to pass multiple kprobe data to link_create attr uapi.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-9-jolsa@kernel.org

Move the kallsyms parsing in internal libbpf_kallsyms_parse
function, so it can be used from other places.

It will be used in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-8-jolsa@kernel.org

Add support for setting the new batch_size parameter to BPF_PROG_TEST_RUN
to libbpf; just add it as an option and pass it through to the kernel.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220309105346.100053-4-toke@redhat.com

Fix the following coccicheck warning:
tools/lib/bpf/bpf.c:114:31-32: WARNING: Use ARRAY_SIZE
tools/lib/bpf/xsk.c:484:34-35: WARNING: Use ARRAY_SIZE
tools/lib/bpf/xsk.c:485:35-36: WARNING: Use ARRAY_SIZE

It has been tested with gcc (Debian 8.3.0-6) 8.3.0 on x86_64.

Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220306023426.19324-1-guozhengkui@vivo.com

xsk_umem__create() does mmap for fill/comp rings, but xsk_umem__delete()
doesn't do the unmap. This works fine for regular cases, because
xsk_socket__delete() does unmap for the rings. But for the case that
xsk_socket__create_shared() fails, umem rings are not unmapped.

fill_save/comp_save are checked to determine if rings have already be
unmapped by xsk. If fill_save and comp_save are NULL, it means that the
rings have already been used by xsk. Then they are supposed to be
unmapped by xsk_socket__delete(). Otherwise, xsk_umem__delete() does the
unmap.

Fixes: 2f6324a3 ("libbpf: Support shared umems between queues and devices")
Signed-off-by: Cheng Li <lic121@chinatelecom.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220301132623.GA19995@vscode.7~

Allow registering and unregistering custom handlers for BPF program.
This allows user applications and libraries to plug into libbpf's
declarative SEC() definition handling logic. This allows to offload
complex and intricate custom logic into external libraries, but still
provide a great user experience.

One such example is USDT handling library, which has a lot of code and
complexity which doesn't make sense to put into libbpf directly, but it
would be really great for users to be able to specify BPF programs with
something like SEC("usdt/<path-to-binary>:<usdt_provider>:<usdt_name>")
and have correct BPF program type set (BPF_PROGRAM_TYPE_KPROBE, as it is
uprobe) and even support BPF skeleton's auto-attach logic.

In some cases, it might be even good idea to override libbpf's default
handling, like for SEC("perf_event") programs. With custom library, it's
possible to extend logic to support specifying perf event specification
right there in SEC() definition without burdening libbpf with lots of
custom logic or extra library dependecies (e.g., libpfm4). With current
patch it's possible to override libbpf's SEC("perf_event") handling and
specify a completely custom ones.

Further, it's possible to specify a generic fallback handling for any
SEC() that doesn't match any other custom or standard libbpf handlers.
This allows to accommodate whatever legacy use cases there might be, if
necessary.

See doc comments for libbpf_register_prog_handler() and
libbpf_unregister_prog_handler() for detailed semantics.

This patch also bumps libbpf development version to v0.8 and adds new
APIs there.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20220305010129.1549719-3-andrii@kernel.org

Allow some BPF program types to support auto-attach only in subste of
cases. Currently, if some BPF program type specifies attach callback, it
is assumed that during skeleton attach operation all such programs
either successfully attach or entire skeleton attachment fails. If some
program doesn't support auto-attachment from skeleton, such BPF program
types shouldn't have attach callback specified.

This is limiting for cases when, depending on how full the SEC("")
definition is, there could either be enough details to support
auto-attach or there might not be and user has to use some specific API
to provide more details at runtime.

One specific example of such desired behavior might be SEC("uprobe"). If
it's specified as just uprobe auto-attach isn't possible. But if it's
SEC("uprobe/<some_binary>:<some_func>") then there are enough details to
support auto-attach. Note that there is a somewhat subtle difference
between auto-attach behavior of BPF skeleton and using "generic"
bpf_program__attach(prog) (which uses the same attach handlers under the
cover). Skeleton allow some programs within bpf_object to not have
auto-attach implemented and doesn't treat that as an error. Instead such
BPF programs are just skipped during skeleton's (optional) attach step.
bpf_program__attach(), on the other hand, is called when user *expects*
auto-attach to work, so if specified program doesn't implement or
doesn't support auto-attach functionality, that will be treated as an
error.

Another improvement to the way libbpf is handling SEC()s would be to not
require providing dummy kernel function name for kprobe. Currently,
SEC("kprobe/whatever") is necessary even if actual kernel function is
determined by user at runtime and bpf_program__attach_kprobe() is used
to specify it. With changes in this patch, it's possible to support both
SEC("kprobe") and SEC("kprobe/<actual_kernel_function"), while only in
the latter case auto-attach will be performed. In the former one, such
kprobe will be skipped during skeleton attach operation.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20220305010129.1549719-2-andrii@kernel.org

The page_cnt parameter is used to specify the number of memory pages
allocated for each per-CPU buffer, it must be non-zero and a power of 2.

Currently, the __perf_buffer__new() function attempts to validate that
the page_cnt is a power of 2 but forgets checking for the case where
page_cnt is zero, we can fix it by replacing 'page_cnt & (page_cnt - 1)'
with 'page_cnt == 0 || (page_cnt & (page_cnt - 1))'.

If so, we also don't need to add a check in perf_buffer__new_v0_6_0() to
make sure that page_cnt is non-zero and the check for zero in
perf_buffer__new_raw_v0_6_0() can also be removed.

The code will be cleaner and more readable.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220303005921.53436-1-ytcoode@gmail.com

Currently if a declaration appears in the BTF before the definition, the
definition is dumped as a conflicting name, e.g.:

    $ bpftool btf dump file vmlinux format raw | grep "'unix_sock'"
    [81287] FWD 'unix_sock' fwd_kind=struct
    [89336] STRUCT 'unix_sock' size=1024 vlen=14

    $ bpftool btf dump file vmlinux format c | grep "struct unix_sock"
    struct unix_sock;
    struct unix_sock___2 {	<--- conflict, the "___2" is unexpected
		    struct unix_sock___2 *unix_sk;

This causes a compilation error if the dump output is used as a header file.

Fix it by skipping declaration when counting duplicated type names.

Fixes: 351131b5 ("libbpf: add btf_dump API for BTF-to-C conversion")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220301053250.1464204-2-xukuohai@huawei.com

When a BPF map of type BPF_MAP_TYPE_PERF_EVENT_ARRAY doesn't have the
max_entries parameter set, the map will be created with max_entries set
to the number of available CPUs. When we try to reuse such a pinned map,
map_is_reuse_compat will return false, as max_entries in the map
definition differs from max_entries of the existing map, causing the
following error:

  libbpf: couldn't reuse pinned map at '/sys/fs/bpf/m_logging': parameter mismatch

Fix this by overwriting max_entries in the map definition. For this to
work, we need to do this in bpf_object__create_maps, before calling
bpf_object__reuse_map.

Fixes: 57a00f41 ("libbpf: Add auto-pinning of maps when loading BPF objects")
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220225152355.315204-1-stijn@linux-ipv6.be

The check in the last return statement is unnecessary, we can just return
the ret variable.

But we can simplify the function further by returning 0 immediately if we
find the section size and -ENOENT otherwise.

Thus we can also remove the ret variable.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220223085244.3058118-1-ytcoode@gmail.com

The existing API perf_thread_map__new_dummy() allocates new thread map
for one thread. I couldn't find a way to reallocate the map with more
threads, or to allocate a new map for more than one thread.

Having multiple threads in a thread map is essential for some use cases.
That's why a new API is proposed, which allocates a new thread map for
given number of threads: perf_thread_map__new_array()

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/linux-perf-users/20220221102628.43904-1-tz.stoyanov@gmail.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The "int thread" input arguments of some perf_thead_map APIs are index
of the thread in the thread map.

In order to avoid confusion and to make the APIs consistent with
perf_cpu_map APIs, those arguments are renamed to "int idx".

Suggested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20220221102612.43879-1-tz.stoyanov@gmail.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The check 't->size && t->size != size' is redundant because if t->size
compares unequal to 0, we will just skip straight to sorting variables.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220220072750.209215-1-ytcoode@gmail.com

Merge radix-tree definitions from gfp.h and slab.h with these
in tools/lib, so they can be used in other test suites.
Fix style issues in slab.h. Update radix-tree test files.

Signed-off-by: Karolina Drobnik <karolinadrobnik@gmail.com>
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Link: https://lore.kernel.org/r/b76ddb8a12fdf9870b55c1401213e44f5e0d0da3.1643796665.git.karolinadrobnik@gmail.com

Ensure that libbpf_netlink_recv() frees dynamically allocated buffer in
all code paths.

Fixes: 9c3de619 ("libbpf: Use dynamically allocated buffer when receiving netlink messages")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20220217073958.276959-1-andrii@kernel.org

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(next-20220214$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

UAPI and wireless changes were intentionally excluded from this patch
and will be sent out separately.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78


Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Expose bpf_core_add_cands() and bpf_core_free_cands() to handle
candidates list.

Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
Signed-off-by: Rafael David Tinoco <rafael.tinoco@aquasec.com>
Signed-off-by: Lorenzo Fontana <lorenzo.fontana@elastic.co>
Signed-off-by: Leonardo Di Donato <leonardo.didonato@elastic.co>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220215225856.671072-3-mauricio@kinvolk.io

BTFGen needs to run the core relocation logic in order to understand
what are the types involved in a given relocation.

Currently bpf_core_apply_relo() calculates and **applies** a relocation
to an instruction. Having both operations in the same function makes it
difficult to only calculate the relocation without patching the
instruction. This commit splits that logic in two different phases: (1)
calculate the relocation and (2) patch the instruction.

For the first phase bpf_core_apply_relo() is renamed to
bpf_core_calc_relo_insn() who is now only on charge of calculating the
relocation, the second phase uses the already existing
bpf_core_patch_insn(). bpf_object__relocate_core() uses both of them and
the BTFGen will use only bpf_core_calc_relo_insn().

Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
Signed-off-by: Rafael David Tinoco <rafael.tinoco@aquasec.com>
Signed-off-by: Lorenzo Fontana <lorenzo.fontana@elastic.co>
Signed-off-by: Leonardo Di Donato <leonardo.didonato@elastic.co>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220215225856.671072-2-mauricio@kinvolk.io

GCC 12 correctly reports a potential use-after-free condition in the
xrealloc helper. Fix the warning by avoiding an implicit "free(ptr)"
when size == 0:

In file included from help.c:12:
In function 'xrealloc',
    inlined from 'add_cmdname' at help.c:24:2: subcmd-util.h:56:23: error: pointer may be used after 'realloc' [-Werror=use-after-free]
   56 |                 ret = realloc(ptr, size);
      |                       ^~~~~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to 'realloc' here
   52 |         void *ret = realloc(ptr, size);
      |                     ^~~~~~~~~~~~~~~~~~
subcmd-util.h:58:31: error: pointer may be used after 'realloc' [-Werror=use-after-free]
   58 |                         ret = realloc(ptr, 1);
      |                               ^~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to 'realloc' here
   52 |         void *ret = realloc(ptr, size);
      |                     ^~~~~~~~~~~~~~~~~~

Fixes: 2f4ce5ec ("perf tools: Finalize subcmd independence")
Reported-by: Valdis Klētnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Kees Kook <keescook@chromium.org>
Tested-by: Valdis Klētnieks <valdis.kletnieks@vt.edu>
Tested-by: Justin M. Forbes <jforbes@fedoraproject.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-hardening@vger.kernel.org
Cc: Valdis Klētnieks <valdis.kletnieks@vt.edu>
Link: http://lore.kernel.org/lkml/20220213182443.4037039-1-keescook@chromium.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Tzvetomir Stoyanov reported an issue with using macro
perf_cpu_map__for_each_cpu using private perf_cpu object.

The issue is caused by recent change that wrapped cpu in struct perf_cpu
to distinguish it from cpu indexes. We need to make struct perf_cpu
public.

Add a simple test for using the perf_cpu_map__for_each_cpu macro.

Fixes: 6d18804b ("perf cpumap: Give CPUs their own type")
Reported-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20220215153713.31395-1-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Commit a7f3713f ("libperf tests: Add test_stat_multiplexing test")
added printf's of 64-bit ints using %lu which doesn't work on 32-bit
builds:

  tests/test-evlist.c:529:29: error: format ‘%lu’ expects argument of type \
    ‘long unsigned int’, but argument 4 has type ‘uint64_t’ {aka ‘long long unsigned int’} [-Werror=format=]

Use PRIu64 instead which works on both 32-bit and 64-bit systems.

Fixes: a7f3713f ("libperf tests: Add test_stat_multiplexing test")
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Link: https://lore.kernel.org/r/20220201213903.699656-1-robh@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

When receiving netlink messages, libbpf was using a statically allocated
stack buffer of 4k bytes. This happened to work fine on systems with a 4k
page size, but on systems with larger page sizes it can lead to truncated
messages. The user-visible impact of this was that libbpf would insist no
XDP program was attached to some interfaces because that bit of the netlink
message got chopped off.

Fix this by switching to a dynamically allocated buffer; we borrow the
approach from iproute2 of using recvmsg() with MSG_PEEK|MSG_TRUNC to get
the actual size of the pending message before receiving it, adjusting the
buffer as necessary. While we're at it, also add retries on interrupted
system calls around the recvmsg() call.

v2:
  - Move peek logic to libbpf_netlink_recv(), don't double free on ENOMEM.

Fixes: 8bbb77b7 ("libbpf: Add various netlink helpers")
Reported-by: Zhiqian Guan <zhguan@redhat.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20220211234819.612288-1-toke@redhat.com

Ensure that LIBBPF_0.7.0 inherits everything from LIBBPF_0.6.0.

Fixes: dbdd2c7f ("libbpf: Add API to get/set log_level at per-program level")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220211205235.2089104-1-andrii@kernel.org

Prepare light skeleton to be used in the kernel module and in the user space.
The look and feel of lskel.h is mostly the same with the difference that for
user space the skel->rodata is the same pointer before and after skel_load
operation, while in the kernel the skel->rodata after skel_open and the
skel->rodata after skel_load are different pointers.
Typical usage of skeleton remains the same for kernel and user space:
skel = my_bpf__open();
skel->rodata->my_global_var = init_val;
err = my_bpf__load(skel);
err = my_bpf__attach(skel);
// access skel->rodata->my_global_var;
// access skel->bss->another_var;

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209232001.27490-3-alexei.starovoitov@gmail.com

Introduce a function to duplicate an existing file descriptor in
the fdarray structure. The function returns the position of the duplicated
file descriptor.

Reviewed-by: Riccardo Mancini <rickyman7@gmail.com>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Namhyung Kim <namhyung@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/2891f1def287d5863cc82683a4d5879195c8d90c.1642440724.git.alexey.v.bayduraev@linux.intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

On ppc64le architecture __s64 is long int and requires %ld. Cast to
ssize_t and use %zd to avoid architecture-specific specifiers.

Fixes: 4172843e ("libbpf: Fix signedness bug in btf_dump_array_data()")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220209063909.1268319-1-andrii@kernel.org