Andrii Nakryiko says:
====================
bpf-next 2021-12-10 v2
We've added 115 non-merge commits during the last 26 day(s) which contain
a total of 182 files changed, 5747 insertions(+), 2564 deletions(-).
The main changes are:
1) Various samples fixes, from Alexander Lobakin.
2) BPF CO-RE support in kernel and light skeleton, from Alexei Starovoitov.
3) A batch of new unified APIs for libbpf, logging improvements, version
querying, etc. Also a batch of old deprecations for old APIs and various
bug fixes, in preparation for libbpf 1.0, from Andrii Nakryiko.
4) BPF documentation reorganization and improvements, from Christoph Hellwig
and Dave Tucker.
5) Support for declarative initialization of BPF_MAP_TYPE_PROG_ARRAY in
libbpf, from Hengqi Chen.
6) Verifier log fixes, from Hou Tao.
7) Runtime-bounded loops support with bpf_loop() helper, from Joanne Koong.
8) Extend branch record capturing to all platforms that support it,
from Kajol Jain.
9) Light skeleton codegen improvements, from Kumar Kartikeya Dwivedi.
10) bpftool doc-generating script improvements, from Quentin Monnet.
11) Two libbpf v0.6 bug fixes, from Shuyi Cheng and Vincent Minet.
12) Deprecation warning fix for perf/bpf_counter, from Song Liu.
13) MAX_TAIL_CALL_CNT unification and MIPS build fix for libbpf,
from Tiezhu Yang.
14) BTF_KING_TYPE_TAG follow-up fixes, from Yonghong Song.
15) Selftests fixes and improvements, from Ilya Leoshkevich, Jean-Philippe
Brucker, Jiri Olsa, Maxim Mikityanskiy, Tirthendu Sarkar, Yucong Sun,
and others.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (115 commits)
libbpf: Add "bool skipped" to struct bpf_map
libbpf: Fix typo in btf__dedup@LIBBPF_0.0.2 definition
bpftool: Switch bpf_object__load_xattr() to bpf_object__load()
selftests/bpf: Remove the only use of deprecated bpf_object__load_xattr()
selftests/bpf: Add test for libbpf's custom log_buf behavior
selftests/bpf: Replace all uses of bpf_load_btf() with bpf_btf_load()
libbpf: Deprecate bpf_object__load_xattr()
libbpf: Add per-program log buffer setter and getter
libbpf: Preserve kernel error code and remove kprobe prog type guessing
libbpf: Improve logging around BPF program loading
libbpf: Allow passing user log setting through bpf_object_open_opts
libbpf: Allow passing preallocated log_buf when loading BTF into kernel
libbpf: Add OPTS-based bpf_btf_load() API
libbpf: Fix bpf_prog_load() log_buf logic for log_level 0
samples/bpf: Remove unneeded variable
bpf: Remove redundant assignment to pointer t
selftests/bpf: Fix a compilation warning
perf/bpf_counter: Use bpf_map_create instead of bpf_create_map
samples: bpf: Fix 'unknown warning group' build warning on Clang
samples: bpf: Fix xdp_sample_user.o linking with Clang
...
====================
Link: https://lore.kernel.org/r/20211210234746.2100561-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Fix error: "failed to pin map: Bad file descriptor, path:
/sys/fs/bpf/_rodata_str1_1."
In the old kernel, the global data map will not be created, see [0]. So
we should skip the pinning of the global data map to avoid
bpf_object__pin_maps returning error. Therefore, when the map is not
created, we mark “map->skipped" as true and then check during relocation
and during pinning.
Fixes: 16e0c35c6f ("libbpf: Load global data maps lazily on legacy kernels")
Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Deprecate non-extensible bpf_object__load_xattr() in v0.8 ([0]).
With log_level control through bpf_object_open_opts or
bpf_program__set_log_level(), we are finally at the point where
bpf_object__load_xattr() doesn't provide any functionality that can't be
accessed through other (better) ways. The other feature,
target_btf_path, is also controllable through bpf_object_open_opts.
[0] Closes: https://github.com/libbpf/libbpf/issues/289
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-9-andrii@kernel.org
Allow to set user-provided log buffer on a per-program basis ([0]). This
gives great deal of flexibility in terms of which programs are loaded
with logging enabled and where corresponding logs go.
Log buffer set with bpf_program__set_log_buf() overrides kernel_log_buf
and kernel_log_size settings set at bpf_object open time through
bpf_object_open_opts, if any.
Adjust bpf_object_load_prog_instance() logic to not perform own log buf
allocation and load retry if custom log buffer is provided by the user.
[0] Closes: https://github.com/libbpf/libbpf/issues/418
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-8-andrii@kernel.org
Instead of rewriting error code returned by the kernel of prog load with
libbpf-sepcific variants pass through the original error.
There is now also no need to have a backup generic -LIBBPF_ERRNO__LOAD
fallback error as bpf_prog_load() guarantees that errno will be properly
set no matter what.
Also drop a completely outdated and pretty useless BPF_PROG_TYPE_KPROBE
guess logic. It's not necessary and neither it's helpful in modern BPF
applications.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-7-andrii@kernel.org
Add missing "prog '%s': " prefixes in few places and use consistently
markers for beginning and end of program load logs. Here's an example of
log output:
libbpf: prog 'handler': BPF program load failed: Permission denied
libbpf: -- BEGIN PROG LOAD LOG ---
arg#0 reference type('UNKNOWN ') size cannot be determined: -22
; out1 = in1;
0: (18) r1 = 0xffffc9000cdcc000
2: (61) r1 = *(u32 *)(r1 +0)
...
81: (63) *(u32 *)(r4 +0) = r5
R1_w=map_value(id=0,off=16,ks=4,vs=20,imm=0) R4=map_value(id=0,off=400,ks=4,vs=16,imm=0)
invalid access to map value, value_size=16 off=400 size=4
R4 min value is outside of the allowed memory range
processed 63 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
-- END PROG LOAD LOG --
libbpf: failed to load program 'handler'
libbpf: failed to load object 'test_skeleton'
The entire verifier log, including BEGIN and END markers are now always
youtput during a single print callback call. This should make it much
easier to post-process or parse it, if necessary. It's not an explicit
API guarantee, but it can be reasonably expected to stay like that.
Also __bpf_object__open is renamed to bpf_object_open() as it's always
an adventure to find the exact function that implements bpf_object's
open phase, so drop the double underscored and use internal libbpf
naming convention.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-6-andrii@kernel.org
Allow users to provide their own custom log_buf, log_size, and log_level
at bpf_object level through bpf_object_open_opts. This log_buf will be
used during BTF loading. Subsequent patch will use same log_buf during
BPF program loading, unless overriden at per-bpf_program level.
When such custom log_buf is provided, libbpf won't be attempting
retrying loading of BTF to try to provide its own log buffer to capture
kernel's error log output. User is responsible to provide big enough
buffer, otherwise they run a risk of getting -ENOSPC error from the
bpf() syscall.
See also comments in bpf_object_open_opts regarding log_level and
log_buf interactions.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-5-andrii@kernel.org
Add libbpf-internal btf_load_into_kernel() that allows to pass
preallocated log_buf and custom log_level to be passed into kernel
during BPF_BTF_LOAD call. When custom log_buf is provided,
btf_load_into_kernel() won't attempt an retry with automatically
allocated internal temporary buffer to capture BTF validation log.
It's important to note the relation between log_buf and log_level, which
slightly deviates from stricter kernel logic. From kernel's POV, if
log_buf is specified, log_level has to be > 0, and vice versa. While
kernel has good reasons to request such "sanity, this, in practice, is
a bit unconvenient and restrictive for libbpf's high-level bpf_object APIs.
So libbpf will allow to set non-NULL log_buf and log_level == 0. This is
fine and means to attempt to load BTF without logging requested, but if
it failes, retry the load with custom log_buf and log_level 1. Similar
logic will be implemented for program loading. In practice this means
that users can provide custom log buffer just in case error happens, but
not really request slower verbose logging all the time. This is also
consistent with libbpf behavior when custom log_buf is not set: libbpf
first tries to load everything with log_level=0, and only if error
happens allocates internal log buffer and retries with log_level=1.
Also, while at it, make BTF validation log more obvious and follow the log
pattern libbpf is using for dumping BPF verifier log during
BPF_PROG_LOAD. BTF loading resulting in an error will look like this:
libbpf: BTF loading error: -22
libbpf: -- BEGIN BTF LOAD LOG ---
magic: 0xeb9f
version: 1
flags: 0x0
hdr_len: 24
type_off: 0
type_len: 1040
str_off: 1040
str_len: 2063598257
btf_total_size: 1753
Total section length too long
-- END BTF LOAD LOG --
libbpf: Error loading .BTF into kernel: -22. BTF is optional, ignoring.
This makes it much easier to find relevant parts in libbpf log output.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-4-andrii@kernel.org
Similar to previous bpf_prog_load() and bpf_map_create() APIs, add
bpf_btf_load() API which is taking optional OPTS struct. Schedule
bpf_load_btf() for deprecation in v0.8 ([0]).
This makes naming consistent with BPF_BTF_LOAD command, sets up an API
for extensibility in the future, moves options parameters (log-related
fields) into optional options, and also allows to pass log_level
directly.
It also removes log buffer auto-allocation logic from low-level API
(consistent with bpf_prog_load() behavior), but preserves a special
treatment of log_level == 0 with non-NULL log_buf, which matches
low-level bpf_prog_load() and high-level libbpf APIs for BTF and program
loading behaviors.
[0] Closes: https://github.com/libbpf/libbpf/issues/419
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-3-andrii@kernel.org
To unify libbpf APIs behavior w.r.t. log_buf and log_level, fix
bpf_prog_load() to follow the same logic as bpf_btf_load() and
high-level bpf_object__load() API will follow in the subsequent patches:
- if log_level is 0 and non-NULL log_buf is provided by a user, attempt
load operation initially with no log_buf and log_level set;
- if successful, we are done, return new FD;
- on error, retry the load operation with log_level bumped to 1 and
log_buf set; this way verbose logging will be requested only when we
are sure that there is a failure, but will be fast in the
common/expected success case.
Of course, user can still specify log_level > 0 from the very beginning
to force log collection.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-2-andrii@kernel.org
This adds comments above functions in libbpf.h which document
their uses. These comments are of a format that doxygen and sphinx
can pick up and render. These are rendered by libbpf.readthedocs.org
These doc comments are for:
- bpf_object__open_file()
- bpf_object__open_mem()
- bpf_program__attach_uprobe()
- bpf_program__attach_uprobe_opts()
Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211206203709.332530-1-grantseltzer@gmail.com
bpf_prog_load_xattr() is high-level API that's named as a low-level
BPF_PROG_LOAD wrapper APIs, but it actually operates on struct
bpf_object. It's badly and confusingly misnamed as it will load all the
progs insige bpf_object, returning prog_fd of the very first BPF
program. It also has a bunch of ad-hoc things like log_level override,
map_ifindex auto-setting, etc. All this can be expressed more explicitly
and cleanly through existing libbpf APIs. This patch marks
bpf_prog_load_xattr() for deprecation in libbpf v0.8 ([0]).
[0] Closes: https://github.com/libbpf/libbpf/issues/308
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-10-andrii@kernel.org
Add bpf_program__set_log_level() and bpf_program__log_level() to fetch
and adjust log_level sent during BPF_PROG_LOAD command. This allows to
selectively request more or less verbose output in BPF verifier log.
Also bump libbpf version to 0.7 and make these APIs the first in v0.7.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211201232824.3166325-3-andrii@kernel.org
Without lskel the CO-RE relocations are processed by libbpf before any other
work is done. Instead, when lskel is needed, remember relocation as RELO_CORE
kind. Then when loader prog is generated for a given bpf program pass CO-RE
relos of that program to gen loader via bpf_gen__record_relo_core(). The gen
loader will remember them as-is and pass it later as-is into the kernel.
The normal libbpf flow is to process CO-RE early before call relos happen. In
case of gen_loader the core relos have to be added to other relos to be copied
together when bpf static function is appended in different places to other main
bpf progs. During the copy the append_subprog_relos() will adjust insn_idx for
normal relos and for RELO_CORE kind too. When that is done each struct
reloc_desc has good relos for specific main prog.
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/20211201181040.23337-10-alexei.starovoitov@gmail.com
struct bpf_core_relo is generated by llvm and processed by libbpf.
It's a de-facto uapi.
With CO-RE in the kernel the struct bpf_core_relo becomes uapi de-jure.
Add an ability to pass a set of 'struct bpf_core_relo' to prog_load command
and let the kernel perform CO-RE relocations.
Note the struct bpf_line_info and struct bpf_func_info have the same
layout when passed from LLVM to libbpf and from libbpf to the kernel
except "insn_off" fields means "byte offset" when LLVM generates it.
Then libbpf converts it to "insn index" to pass to the kernel.
The struct bpf_core_relo's "insn_off" field is always "byte offset".
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/20211201181040.23337-6-alexei.starovoitov@gmail.com
enum bpf_core_relo_kind is generated by llvm and processed by libbpf.
It's a de-facto uapi.
With CO-RE in the kernel the bpf_core_relo_kind values become uapi de-jure.
Also rename them with BPF_CORE_ prefix to distinguish from conflicting names in
bpf_core_read.h. The enums bpf_field_info_kind, bpf_type_id_kind,
bpf_type_info_kind, bpf_enum_value_kind are passing different values from bpf
program into llvm.
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/20211201181040.23337-5-alexei.starovoitov@gmail.com
Make relo_core.c to be compiled for the kernel and for user space libbpf.
Note the patch is reducing BPF_CORE_SPEC_MAX_LEN from 64 to 32.
This is the maximum number of nested structs and arrays.
For example:
struct sample {
int a;
struct {
int b[10];
};
};
struct sample *s = ...;
int *y = &s->b[5];
This field access is encoded as "0:1:0:5" and spec len is 4.
The follow up patch might bump it back to 64.
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/20211201181040.23337-4-alexei.starovoitov@gmail.com
To prepare relo_core.c to be compiled in the kernel and the user space
replace btf__type_by_id with btf_type_by_id.
In libbpf btf__type_by_id and btf_type_by_id have different behavior.
bpf_core_apply_relo_insn() needs behavior of uapi btf__type_by_id
vs internal btf_type_by_id, but type_id range check is already done
in bpf_core_apply_relo(), so it's safe to replace it everywhere.
The kernel btf_type_by_id() does the check anyway. It doesn't hurt.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
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/20211201181040.23337-2-alexei.starovoitov@gmail.com
